Exam 3 (Chapters 7-9) Flashcards
A variable that involves a manipulation with a level that involves the treatment and a level that does not involve the treatment
Presents-absence variable
An independent variable with 2 levels- a design is considered bivalent if it contains only one bivalent independent variable
Bivalent independent variable
A variable that involves a manipulation of types of treatments
Type variable
A variable that includes levels with a different amount of the treatment changing from level to level
Amount variable
An independent variable that includes 3 or more levels- a design is considered multivalent if there is only one independent variable that contains 3 or more levels
Multivalent variable
Variable that allows comparison of groups of participants without manipulation (i.e. No random assignment)
Quasi-independent or subject variable
A study or scale appearing to be intuitively valid on the surface
Face validity
Participant groups are not equated on characteristics that can affect the data is which source of bias?
Group differences
1.Gender
2.Previous knowledge or experience with a task
3.Current mood state affect the scores
Are all good examples of which source of bias?
Group differences
Which type of validity is threatened by the group differences source of bias?
Internal
Order of conditions in a within-subjects design can affect data collected in different conditions is which source of bias?
Order effects
When easy tasks precede difficult tasks or positive experiences precede negative experiences.
This is an example of which source of bias?
Order effects
Which type of validity is threatened by the order effects source of bias?
Internal
There are multiple testing sessions- 1st testing effects subsequent testing is describing which source of bias?
Testing effects
Scores are changed based on practice effects, fatigue effects, or accumulated knowledge of the task.
This is an example of which source of bias?
Testing effects
Which type of validity is threatened by testing effects source of bias?
Internal
Extreme scores are unlikely to recur is describing which source of bias?
Regression toward the mean.
- A student earns a high score on a test in class but has a low average course grade.
- A professional athlete has a high performing year compared with his or her average performance
This is a good example of which source of bias?
Regression toward the mean
What type of validity is threatened by regression toward the mean source of bias?
Internal
The researcher treats different groups of participants in different ways based on knowledge of the study is describing which source of bias?
Experimenter bias
The instructor spends more time discussing material in a class he knows is not receiving a new teaching technique designed to improve learning.
This is a good example of which source of bias?
Experimenter bias
What type of validity is threatened by experimenter bias?
Internal
Participants provide survey responses to present themselves in a more positive way is describing which source of bias?
Social desirability
A participant responds to items on an anxiety survey with lower values than his or her actual level of anxiety.
This is an example of which source of bias?
Social desirability
Which type of validity is threatened by social desirability source of bias?
Internal
Some participants choose not to or are unable to complete a study, biasing the sample describes which source of bias?
Attrition or mortality
Less conscientious participants do not complete all sessions of a multi session study.
This is a good example of which source of bias?
Attrition or mortality
Which type of validity is threatened by attrition or mortality source of bias?
Internal and external
Studying participants can change their behavior describes which source of bias?
Hawthorne effect
1.Workers productivity improves when they know they are being studied
2. participants perform better in a memory study than they would outside the study
These are good examples of which source of bias?
Hawthorne effect
Which type of validity is threatened by Hawthorne effect source of bias?
External
Procedure used to hide the group assignment from the participants in a study to prevent their beliefs about the effectiveness of a treatment from affecting the results
Single-blind design
Procedure used to control for experimenter bias by keeping the knowledge of the group assignments from both the participants and the researchers who interact with the participants
Double-blind design
A source of bias and a study created when a researcher treats groups differently (often unknowingly) based on knowledge of the hypothesis
Experimenter bias
Occur when participants are tested more than once in a study- with early testing affecting later testing
Testing effects
Participant experiences all levels of the independent variable
Within-subjects variable
A control used in within-subjects experiments where equal numbers of participants are randomly assigned to different orders of the conditions
Counterbalancing
Can occur when participants score higher or lower than their personal average- the next time they are tested, they are more likely to score near their personal average, making scores unreliable
Regression toward the mean
Occurs when participants choose not to complete a study
Attrition or mortality
A source of bias that can occur in a study due to participants changing their behavior because they are aware that they are being observed
Hawthorne effect
If a score on a midterm is unusually high for a student and far above his or her mean grade in the class to date, this would represent ____________ as a score of bias in using the midterm score to measure his or her learning in the course.
Regression toward the mean
A ___________ design is often used to prevent experimental bias, such that neither the researcher nor the subject is aware of the condition the subject has been assigned to in the study.
double-blind
Suppose a researcher wants to study work productivity and a factory. Video cameras are installed to see how much time worker spend on task during a work day. The workers are more productive on the day after the cameras are installed than on the day before. A possible cause of the increase in productivity that would represent a source of bias and the study is ____________.
the Hawthorne effect
A researcher is interested in studying face recognition ability. Subjects are tested in the lab on their recognition of photos of unknown faces presented on a computer screen. If the subject’s process the photos of the faces in a way that is different from how they typically process faces and their daily lives, this study would suffer from low _____________ validity.
External
Explain why attrition or mortality is a possible source of bias when it occurs in a research study.
Attrition occurs when subjects drop out of a study before it is completed. The problem with attrition is that the subjects who drop out may be characteristically different from subjects who remain in the study. This can result in data that only apply to certain members of the group being studied, which can limit the conclusions a researcher can draw from the results of the study.
Causal relationships are best tested with _________.
A. Correlational studies
B. A manipulated independent variable
C. Quasi-independent variables
D. Confounding variables
B. A manipulated independent variable
Experimenter bias is best controlled by a __________ design.
A. Single-blind
B. Double-blind
C. Regression
D. Demand characteristics
B. Double-blind
As a researcher controls sources of bias in a study, ___________ will increase.
A. Internal validity
B. External validity
C. Demand characteristics
D. Regression toward the mean
A. Internal Validity
As confounding variables are controlled more in a study, _________ often will decrease.
A. Internal validity
B. External validity
C. Counterbalancing
D. Placebos
B. External Validity
A quasi-independent variable is the same as a(n) ______.
A. subject variable
B. independent variable
C. dependent variable
D. confounding variable
A. Subject Variable
Any characteristic that can be measured or observed from the participants can be used to create a(n) ______ variable in a study.
A. bivalent
B. independent
C. quasi-independent
D. dependent
C. Quasi-independent
Researcher treats different groups of participants in different ways based on knowledge of the study is ______.
A. confound
B. researcher bias
C. testing effects
D. Hawthorne effect
A. Confound
Independent variables can be manipulated according to all but ______.
A. presence/absence of treatment
B. type of treatment
C. amount of treatment
D. level of treatment
D. Level of treatment
A study with good internal validity provides a good test of a causal relationship by removing ______ of the data
A. researcher bias
B. alternative explanations
C. invalid scores
D. confounds
B. Alternative explanations
In a ______, both the participants and the researchers who interact with the participants do not know which participants are assigned to the different groups.
A. double-blind design
B. tri-blind design
C. multi-blind design
D. single-blind design
A. Double-Blind design
Having different participants in a study experience conditions in different orders is ______.
A. counterbalancing
B. regression toward the mean
C. random assignment
D. attrition
A. Counterbalancing
______ is a source of bias that can occur in a study due to participants changing their behavior based on their perception of the study and its purpose.
A. Demand characteristics
B. Perception characteristics
C. Bias characteristics
D. Study characteristics
A. Demand characteristics
In the ______ design, each participant experiences only one level of the independent variable.
A. within-subjects
B. between-subjects
C. across-subjects
D. all-subjects
B. between-subjects
This occurs when the order in which the participants experience conditions and an experiment affects the results of the study
Order effects
An experiment and a course to compare test scores on an exam for 3 groups of students: One group that studies 5 hours with classical music in the background, One group that studies for 5 hours with pop music in the background, One group that studies for 5 hours with no music.
If the participants are randomly assigned to only one of the condition (classical, pop, none), this is an example of _________-________
Between-subjects design
A between subjects experiment that involves sets of participants matched on a specific characteristic with each member of the set randomly assigned to a different level of the independent variable
Matched design
Consider a study conducted by O’Hanlon and Roberson (2006). They conducted an experiment where they created sets of participants who were matched on age and vocabulary abilities and randomly assigned one member of each match set to a different feedback condition. This is an example of _________ _________
Matched design
The order in which the participants receive the different levels of the independent variable describes _________ __________
Within-subjects experiments
Partial counter balancing technique where the number of orders of conditions used = the number of conditions in the study
Latin square
Type of Psychology that includes the study of basic processes of information from the world around us. They study memory, perception, language processes, and decision making.
Cognitive
Storm and Stone (2015) conducted a simple experiment to investigate the effects of saved saving studied information in a computer file on one’s ability to learn new information. They concluded that saving a file that can be accessed later freeze up cognitive resources for other tasks showing benefits of reliable technology on cognition. This is an example of what type of experiment?
Cognitive experiment example
The type of psychology investigates the role of biological factors in behavior. Can also be called neurosychology if it involves brain function.
Biological psychology
Ferrè, Lopez, and Haggard (2014) Conducted a study To examine the link between the vestibular system (controls are sense of balance) and one’s perspective (own perspective vs. another person’s). It showed that the stimulation of the vestibular system increases 1st person perspective suggesting that this system is involved in our sense of self. This study is an example of what type of experiment?
Biological experiment example
This type of psychologist examines the effects of social factors on different types of behavior
Social psychologist
Bastian, Jetten, and Ferris (2014) Tested the effects of experiencing pain on social bonding Found that subjects in the pain group rated their bonding higher than the subjects in the no pain group. This was an example of which type of experiment?
Social experiment example.
A researcher decided to test whether the presence of another person effects participants task performance. He asked participants to complete a maze puzzle as quickly as they can. Participants complete 2 puzzles: Once on their own and once with a research Confederate present who seems to also be working on the puzzle. Half of the participants complete the puzzle alone 1st, 1/2 complete the puzzle with the Confederate present 1st. Time to complete the puzzle is recorded for each participant for the 2 puzzles they complete.
The dependent variable in the study is ________
A. Completing the maze alone
B. Completing the maze with the Confederate present.
C. Whether or not someone was present when they completed the maze.
D. The time to complete the maze.
D. The time to complete the maze.
A researcher decided to test whether the presence of another person effects participants task performance. He asked participants to complete a maze puzzle as quickly as they can. Participants complete 2 puzzles: Once on their own and once with a research Confederate present who seems to also be working on the puzzle. Half of the participants complete the puzzle alone 1st, 1/2 complete the puzzle with the Confederate present 1st. Time to complete the puzzle is recorded for each participant for the 2 puzzles they complete.
The independent variable in this study is ________.
A. Completing the maze alone.
B. Completing the maze with a Confederate present.
C. Whether or not someone was present when they completed the maze.
D. The time to complete the maze.
C. Whether or not someone was present when they completed the maze.
A researcher decided to test whether the presence of another person effects participants task performance. He asked participants to complete a maze puzzle as quickly as they can. Participants complete 2 puzzles: Once on their own and once with a research Confederate present who seems to also be working on the puzzle. Half of the participants complete the puzzle alone 1st, 1/2 complete the puzzle with the Confederate present 1st. Time to complete the puzzle is recorded for each participant for the 2 puzzles they complete.
This experiment is a ________ design.
A. Between-subjects
B. Within-subjects
C. Mixed
B. Within-subjects
A researcher decided to test whether the presence of another person effects participants task performance. He asked participants to complete a maze puzzle as quickly as they can. Participants complete 2 puzzles: Once on their own and once with a research Confederate present who seems to also be working on the puzzle. Half of the participants complete the puzzle alone 1st, 1/2 complete the puzzle with the Confederate present 1st. Time to complete the puzzle is recorded for each participant for the 2 puzzles they complete.
Having half the participants complete the maze alone 1st 1/2 complete it with the Confederate present 1st is an example of ____________.
A. Using a between-subjects design
B. Using a small-n design
C. Using counterbalancing
C. Using counterbalancing
What aspects of an experiment allowed tests of causal relationships?
Manipulation of an independent variable and control of extraneous variables.
What is the advantage of using a Latin square over full counterbalancing when counterbalancing the order of conditions in a within-subject’s design? How many orders are used in a Latin square?
The Latin square allows fewer orders to be used than a full counterbalancing- useful for designs with more than three conditions. The number of orders in a Latin square matches the number of conditions in the experiment.
A researcher conducted a study to investigate the effects of smiling on helping behavior. Participants completed a survey that they thought was the purpose of the study but in reality the experiment took place after they completed the survey. At the end of the survey session half of the subjects were thanked with a smile 1/2 were thanked without a smile. Whether the subjects received a smile or not was randomly determined. The subjects were on their way out of the lab in the hallway when they passed a Confederate who had just dropped a large stack of books. The number of subjects who helped the Confederate picked up his books for the smile and no smile groups was compared.
A. What is the independent variable in this experiment? Is the independent variable manipulated between-subjects or within-subjects?
B. Can you think of an important ethical issue for this experiment and how to handle it in the procedure of the experiment?
a) The independent variable is smile group: smile or no smile—it is manipulated between-subjects because the subjects only complete the experiment in one of the two groups.
b) The main ethical issue in this study is that deception is used (the subjects are misled about what the study is actually about and what behaviors are being observed). The researchers need to justify why the deception is necessary and thoroughly debrief the subjects at the end of the experiment, so they understand why they were deceived and what the real purpose of the study was.
A study is conducted to examine the effects of office layout on work productivity. Employees in a company are currently organized into cubicles. Their current work productivity, (number of emails sent, number of reports completed) per day is measured for each day and one week. Then the layout is reorganized with employees grouped at small tables set around a large open room according to unit of the company. After getting used to this layout for a month, their work productivity is again measured for each day in one week.
This is a __________ experiment
A. Between-subjects
B. Within-subjects
A. Between-subjects
A study is conducted to examine the effects of office layout on work productivity. Employees in a company are currently organized into cubicles. Their current work productivity, (number of emails sent, number of reports completed) per day is measured for each day and one week. Then the layout is reorganized with employees grouped at small tables set around a large open room according to unit of the company. After getting used to this layout for a month, their work productivity is again measured for each day in one week.
The independent variable in this experiment is ____________.
A. The day of week that productivity was measured on.
B. One week
C. Number of emails sent
D. The office layout
D. The office layout
A study is conducted to examine the effects of office layout on work productivity. Employees in a company are currently organized into cubicles. Their current work productivity, (number of emails sent, number of reports completed) per day is measured for each day and one week. Then the layout is reorganized with employees grouped at small tables set around a large open room according to unit of the company. After getting used to this layout for a month, their work productivity is again measured for each day in one week.
A possible confounding variable in this experiment is __________.
A. Group differences and work productivity.
B. Which day of the week productivity is measured on.
C. Order effects
C. Order effects
Manipulation of an independent variable in a study ______ the internal validity of the study.
A. can decrease or increase
B. does not impact
C. increases
D. decreases
C. increases
______ in an experiment allows the researcher to learn about the causal relationship between the independent and dependent variables.
A. Manipulation of an independent variable
B. Random assignment of subjects
C. Matched design
D. Controlling confounds
A. Manipulation of an independent variable
______ occur(s) when the order in which the participants experience conditions in an experiment affects the results of the study.
A. Hawthorne effects
B. Researcher manipulation
C. Order effects
D. Counterbalancing
C. Order effects
______ design is an experiment conducted with one or a few participants to better understand the behavior of those individuals.
A. Between-subjects
B. Small-n
C. One-factor
D. Within-subjects
B. Small-n
A ______ design is a between-subjects experiment that involves sets of participants matched on a specific characteristic with each member of the set randomly assigned to a different level of the independent variable.
A. significant
B. corresponding
C. paired
D. matched
D. matched
Counterbalancing is ______ when there are only two conditions that participants experience in an experiment.
A. difficult
B. easy
C. impossible
D. pointless
B. Easy
If you are concerned that a group difference is likely to affect your results, it is best to ______ or ______ before assigning them to groups.
A. use a within-subjects manipulation; match participants
B. use random assignment; match participants
C. use between-subjects manipulation; randomly assign participants
D. use software to eliminate in-group differences; match participants
A. use a within-subjects manipulation; match participants
To simplify the counterbalancing, a partial counterbalancing technique, called a(n) ______ square, can be used.
A. Spanish
B. Latin
C. English
D. Canadian
B. Latin
One benefit of within-subject designs is that they control for ______ .
A. carryover effects
B. individual differences
C. contrast effects
D. fatigue effects
B. individual differences
Diana has an independent variable with three levels. She uses a Latin-square design to help ensure that the orders in which participants experience the levels of the independent variable occur equally as often across participants. She is ______ the order of treatments.
A. randomizing
B. counterbalancing
C. squaring
D. matching
B. Counterbalancing
A standardized score that indicates the location of a score within a population distribution
Z score
A symmetrical distribution in which the percentage of scores in each portion of the distribution is known
Normal distribution
A table of the proportion of scores and a normal distribution for many different Z score values
Unit normal table
The estimate of sampling error that is determined from the standard deviation of the distribution of sample means
Standard error
The mathematical description of the shape of the distribution of sample means that states that for a population with mean (mue) and standard deviation (sigma), the distribution of sample means for sample size n will have a mean equal to the mue, a standard deviation equal to the standard error, and a shape approaching a normal distribution as n becomes very large.
Central limit theorem
What are the 5 steps to hypothesis testing
Step 1: State your research question and make hypothesis about the answer.
Step 2: Set a decision criterion for making a decision about the hypothesis.
Step 3: Collect your sample data.
Step 4: Calculate statistics.
Step 5: Make a decision about the hypothesis.
State the research question and develop the null and alternative hypothesis using literature in the research area is what step of the hypothesis testing?
Step 1: State hypothesis
Set the decision criteria alpha as a probability that the sample mean is the score in the distribution of sample means, Consider how your alpha level will influence the chance of type one and type 2 errors in your test. This covers what step of the hypothesis testing?
Step 2: Set decision criterion
Design your study to test your hypothesis, Recruit sample participates or subjects, And collect data on the dependent variables of interest. This covers what step of the hypothesis testing?
Step 3: Collect sample data
The step and hypothesis testing that summarizes data with descriptive statistics. Choose an appropriate inferential statistics test and calculate the inferential statistic and corresponding probability value for that statistic.
Step 4: Calculate statistics
The step of hypothesis testing that compares this statistic P value with alpha level. Make a decision to either reject or retain the knoll hypothesis based on this comparison and then decide if you can accept the alternative hypothesis
Step 5: Make a decision
The hypothesis that an effect or relationship exists ( Or exist in a specific direction) in the population
Scientific or alternative hypothesis (H1)
The hypothesis that an effect or relationship does not exist (Or exist in the opposite direction of the alternative hypothesis) in the population
Null hypothesis (H0)
Both directions of an effect or relationship are considered in the alternative hypothesis of the test
Two-tailed hypothesis
Only one direction of an effect or relationship is predicted in the alternative hypothesis of the test
One-tailed hypothesis
The probability level used by researchers to indicate the cut off probability level (highest value) that allows them to reject the null hypothesis
Alpha level
The most extreme portion of a distribution of statistical values for the null hypothesis determined by the decision criterion (i.e., alpha level- typically 5%)
Critical region
Probability value associated with an inferential test that indicates the likelihood of obtaining the data in a study when the null hypothesis is true
P value
Significance test used to compare means
T test
An error made in a hypothesis test when the researcher rejects the null hypothesis when it is actually true.
Type I error
An error made and I hypothesis test when the researcher fails to reject the null hypothesis when it actually is false.
Type II error
The ability of a hypothesis test to detect an effect or relationship when one exists (equal to 1 minus the probability of a type II error)
Power
P value is less than or equal to the alpha level in an inferential test and the null hypothesis can be rejected
Significant test
Population standard deviation divided by the square root of the sample size
Standard error
Sample mean minus the population mean divided by the standard error
One-sample Z test
A standardized score is _________.
A. A Z score
B. A score that has been transformed to allow comparisons across distributions.
C. A new score that represents the original score’s distance from the distribution mean and standard deviation units.
D. All of the above
D. All of the above
A Z score of -1.45 indicates that ______.
A. The original scores between 1 and 2 standard deviations above the mean.
B. The original scores between 1 and 2 standard deviations below the mean.
C. The original score is not in the population distribution because it is negative.
D. The original score cannot be transformed into a standardized score
B. The original scores between 1 and 2 standard deviations below the mean.
The unit normal table can tell us _______.
A. The Z score for a score in a distribution.
B. The Z scores for all the scores in a distribution.
C. The percentage of scores at a specific Z score or higher in the normal distribution.
D. The percentage of scores at a specific Z score or higher in a skewed distribution.
C. The percentage of scores at a specific Z score or higher in the normal distribution.
For a population with mue = 100 and Sigma = 10, what is the Z score for a score of 90?
A. +10
B. -10
C. +1.0
D. -1.0
D. -1.0
For a population with mue = 100 and Sigma = 10, what is the Z score for a score of 120?
A. +20
B. -20
C. +2.0
D. -2.0
C. +2.0
Calculating a Z score can help us test a hypothesis about a population
A. True
B. False
A. True
A Z score will tell us the distance from the mean of a score in a distribution but not the direction of that location from the mean.
A. True
B. False
B. False
The unit normal table will tell us the exact probability of a Z score in any distribution.
A. True
B. False
B. False
You are taking 2 psychology courses: Cognition and Research Methods. On the same day, you taken an exam in both courses. In Cognition you score a 78 on the exam (mue= 75, sigma= 3), and in Research Methods you score an 82 (mue= 78, sigma= 5). In which class did you actually do better on the exam (relative to the population)?
The Cognition class, where you scored one standard deviation above the mean (z=1). In the Research Methods class, you scored less than one standard deviation above the mean (z=0.8).
Some intelligent tests have a mue=100 and sigma=10. If you score a 110 on an intelligence test with this distribution, What is the Z score for your score?
z=1
Explain why Z scores called a standardized score.
A z-score is a number that compares the original score to the mean of the distribution. It allows for better comparisons of scores from two (or more) different scales.
For each Z score, find the percentage of scores at that value or higher in the normal distribution
A. +1.67
B. -2.02
C. -.80
D. +.08
a.) 5%
b.) 98%
c.) 79%
d.) 47%
Your score on a course exam was 95, And your Z score on this exam was +2.0. The distribution of exams scores had a Sigma=5. What was the mean on the exam?
85
A standardized math test for 5th graders has a mue=50. A student scores 60 on this exam and their Z score is +1.50. What is this Sigma for the standardized test?
6.7
The standard error is _______.
A. Determined from the population standard deviation and the sample size.
B. An estimate of the sampling error.
C. The variability of the distribution of sample means.
D. All of the above
D. All of the above
The alpha level is the _______.
A. Chance that the null hypothesis is true.
B. Chance that the null hypothesis is false.
C. Decision criterion for rejecting the null hypothesis set by the researcher.
C. Decision criterion for rejecting the null hypothesis set by the researcher.
The researchers hypothesis is typically the opposite of the ________ hypothesis.
A. Alternative
B. Null
C. Population
B. Null
The hypothesis testing procedure can provide evidence against the ______.
A. Null hypothesis
B. Alternative hypothesis
C. Distribution of sample means standard error
A. Null Hypothesis
The possible decisions in step 5 of the hypothesis testing procedure are to ________.
A. Reject the null hypothesis
B. Accept the nulll hypothesis
C. Retain the null hypothesis
D. only A and B
E. only A and C
E. only A and C
The hypothesis testing procedure will tell us the probability that the null hypothesis is true.
A. True
B. False
A. True
The best estimates of the population mean and standard deviation when these values are not known are the mean and standard deviation values in the sample.
A. True
B. False
A. True
The inferential test statistic represents the difference between means with sampling error removed.
A. True
B. False
A. True
Explain why errors are always possible during hypothesis testing.
In hypothesis testing, we are relying on a probability—not a certainty—to make a decision. Therefore, errors are possible.
You pulled several all nighters last semester to study for your final exam. You want to know if staying up all night hurt your exam performance so you will know if it is worth it to stay up all night to study. You calculate the means score for all the finals you have ever taken in college (your exam population mue) and find that mue=87% with sigma=5%. Assume you know that this population of scores has a normal distribution. You use as your sample the mean score on all five of the final exams you took last semester, X=83%.
What are the null and alternative hypothesis for this example? Is this a 1 or 2 tailed test?
The alternative hypothesis is: Staying up all night decreased your final exam scores. The null hypothesis is: Staying up all night increased your final exam scores or made no difference. This is a one-tailed test.
You pulled several all nighter last semester to study for your final exam. You want to know if staying up all night hurt your exam performance so you will know if it is worth it to stay up all night to study. You calculate the means score for all the finals you have ever taken in college (your exam population mue) and find that mue=87% with sigma=5%. Assume you know that this population of scores has a normal distribution. You use as your sample the mean score on all five of the final exams you took last semester, X=83%.
Use a one sample Z test to determine if your all nighters hurt your performance.
We can reject the null hypothesis that staying up increases or has no effect on your final exam scores. A z-score of -1.79 shows a probability of 4% (0.037) in the tail of the distribution of sample means, which falls below our alpha level. The results suggest staying up all night decreased your final exam scores.
You pulled several all nighter last semester to study for your final exam. You want to know if staying up all night hurt your exam performance so you will know if it is worth it to stay up all night to study. You calculate the means score for all the finals you have ever taken in college (your exam population mue) and find that mue=87% with sigma=5%. Assume you know that this population of scores has a normal distribution. You use as your sample the mean score on all five of the final exams you took last semester, X=83%.
Suppose that in reality, all nighters do hurt your performance on exams. In this case, what type of decision has occurred in your test?
Correct decision
You pulled several all nighters last semester to study for your final exam. You want to know if staying up all night hurt your exam performance so you will know if it is worth it to stay up all night to study. You calculate the means score for all the finals you have ever taken in college (your exam population mue) and find that mue=87% with sigma=5%. Assume you know that this population of scores has a normal distribution. You use as your sample the mean score on all five of the final exams you took last semester, X=83%.
What is the easiest way to reduce type to error? What problem does this method of reducing type 2 errors create?
Increase the sample size. Enlarging the sample size could result in obtaining a significant difference between groups that is based on subject differences unrelated to the study.
A(n) ______ hypothesis predicts no effect, whereas a(n) ______ hypothesis predicts an effect.
A. one-tailed; two-tailed
B. two-tailed; one-tailed
C. null; alternative
D. alternative; null
C. null; alternative
In a research study, the p value obtained for the inferential statistic is .08. This means that ______.
A. there is an 8% chance of obtaining these data when the null hypothesis is false
B. there is an 8% chance of obtaining these data when the null hypothesis is true
C. there is a 92% chance of obtaining these data when the null hypothesis is true
D. there is a 92% chance of obtaining these data when the null hypothesis is false
B. there is an 8% chance of obtaining these data when the null hypothesis is true.
If we reject the null hypothesis when it’s really true, we have made a ______.
A. correct decision
B. Type I error
C. Type II error
D. Type I and Type II error
B. Type I error
The decision to reject the null hypothesis in a statistical test is made when ______.
A. the researcher cannot conclude that the null is true
B. p < alpha
C. p > alpha
D. the researcher initially sets the alpha level
B. p < alpha
In simple terms, the null hypothesis is that a relationship ______ in the study population.
A. is weak
B. is not significant
C. does not exist
D. does not merit review
C. does not exist
The z score sign (positive or negative) tells us whether the score is above or below the ______.
A. standard p value
B. population mean
C. significance criterion
D. power level
B. Population mean
