Research Methods and Statistics Flashcards
What is a standardised way of making observations, collecting information, creating theories, testing those theories, and interpreting results?
The scientific method
What do psychologists use to conduct research to investigate and explain human behaviour?
Scientific method
What does every experiment begin with?
A hypothesis
What does a hypothesis attempt to do?
Explain the phenomenon on or how separate facts or occurrences are related
Hypothesises must possess what two characteristics?
Testable and falsifiable
What two characteristics must a hypothesis have to account for the entire range of relevant phenomena?
Precise and proper scope
What do precision and operational definitions do to allow research to be replicated in the future?
Eliminate ambiguity
What is the hypothesis principle that the fewest assumptions is always the strongest?
Parsimonious
A successful hypothesis must be able to ____ and ____ future phenomena.
Explain and predict
Since no hypothesis is ever proven to be true, what can be said about hypotheses?
They are supported by evidence or falsified
What is an alternative hypothesis?
A hypothesis compared to a null hypothesis
What is compared to a null hypothesis?
Alternative hypothesis
What does the symbol H1 mean?
Alternative hypothesis
What does the symbol H0 mean?
Null hypothesis
What is a null hypothesis?
A counter-hypothesis that states that there is no relationship between the phenomena under the proposed scope
What do researchers try to do to the null hypothesis? What do researchers try to do to the alternative hypothesis?
Researchers tried to reject the null hypothesis rather than trying to prove the alternate hypothesis
What are variables?
Any behaviours, characteristics, conditions, or occurrences that researchers study
What are the two types of variables?
Independent variables and dependent variables
What are independent variable is also referred to as?
The treatment
What is the independent variable?
The variable that is somehow manipulated by the researcher
What is the dependent variable?
The variable that is hypothesised to be affected by the independent variable and is measured by the researcher
Before conducting any research, it is crucial to establish concrete ______ _______.
Operational definitions
What are operational definitions?
Rules that describe exactly what the variables are in the specific methods used to manipulate and measure them
Scientist describe the medium through which they measure and compare variables in terms of what five things?
1) subject
2) population
3) sample
4) control group
5) experimental group
What is a subject in the experiment?
The human, animal, or thing the researcher studies
What is population experimental design?
The entire collection of subjects from which researchers draw data and hope to draw conclusions about
What is a sample and experimental design?
The collection of subjects drawn from the population and actually used in the study or experiment
A sample must have what two characteristics?
1) be representative of the population
2) sufficiently large in order for any experimental results to be generalisable to the population
What is the control group in experimental design?
The randomly assigned a group of subjects who are not exposed to any experimental conditions
What is the experimental group of experimental design?
The randomly assigned groups of subjects who are exposed to the experimental conditions
What are the three main types of experimental designs allowed researchers to study subjects and compare variables?
1) between subjects design
2) within subjects design
3) mixed factorial design
What groups do subjects participate in in the between – subjects design?
Each subject participates in only one group, either the control group or the experimental group, but not both
What does the between subjects design prevent?
Prevents the likelihood of subjects performing better on tasks due to practice, subject to performing worse due to tiredness, and the likelihood of results been contaminated from the effects of the first treatment
In experimental design, what is the practice/learning affect?
Subjects performing better on tasks due to practice
In experimental design, what is the fatigue effect?
Subjects performing worse due to tiredness, boredom, or distraction
In experimental design, what is the carryover effect?
The likelihood of results being contaminated from the effects of the first treatment influencing the subsequent treatment
What is another term for the within subjects design?
Repeated measures design
What groups do the subjects participate in In the within subjects design?
Each subject participates in every group, is exposed to each treatment, and therefore serves as his or her own control
In that within subjects design, the experiment is more prone to the practice/learning affect, fatigue affects, and carryover effect. How can these negative effects be minimised?
Counterbalanced measures
What are counterbalance measures? In which experimental design are they used?
A design that includes all possible treatment orders, effectively accounting for every situation; with in subject design
What does the mixed factorial design experimental design do?
Combines aspects of the between subjects design and the within subjects design
Describe the variables of the mixed factorial design.
It involves two independent variables, one variable that is measured between subjects and one that is measured within subjects
How are the subjects assigned in the mixed factorial design?
Each subject is randomly assigned to one group and then cycles through the remaining groups
What is the overall goal of an experiment?
To compare measurements of the dependent variable between the control and experimental groups to see whether exposure to the independent variable as an effect on the dependent variable
What are confounding variables?
Certain extraneous variables that cannot be controlled for; they can adversely affect the independent variable–dependent variable relationship, making it difficult to determine the true relationship
What are biases?
Systematic errors in experimental design, execution, or analysis that result in misinterpretations of the relationship between phenomena
What do biases do to research validity?
Decrease research validity
What are the three main types of research bias?
1) selection bias
2) subject bias
3) experimenter bias
When does selection bias occur?
Occurs when the selection of subjects is not properly randomised
What does selection bias result in?
Results in a sample that is not representative of the population, thus making any results invalid for generalisation
What is subject bias?
Describes how a subjects expectations and beliefs about the study will affect his or her performance or behaviour
What are the three types of subject bias’s?
1) placebo effect
2) social desireability
3) demand characteristics
What is the placebo effect?
The phenomenon in which people expect a treatment to work, so it does to some degree, even though they received a fake treatment
What is social desirability?
The tendency for people to describe themselves or report information that is perceived is socially acceptable
What is the effect of demand characteristics?
The tendency for subjects to modify their behaviour to conform to the expectations of the researcher
What is experimenter bias?
Occurs when the objectivity of the experimenter is compromised; experimenters expectations for the study may influence his or her behaviour with the subjects; leading to conclusions that aren’t necessarily supported
What are three ways to reduce bias from an experiment?
1) random assignment
2) blind study
3) double blind study
What is random assignment?
Dividing subjects into groups based purely on chance instead of human decision
What is a blind study?
A study in which all subjects are unaware of what treatment they are receiving
What is a double-blind study?
A study in which neither the subject nor the experimenters are aware of the treatment being administered
What is observational research?
Observational studies involve systematic observation of subjects where researchers look to find important patterns
Does observational research consists of methods that manipulate variables or conduct any experiment?
No variable manipulation or conduction of experiments
In what types of environments is observational research conducted?
Natural or laboratory settings
What is archival research?
Consists of unobtrusive methods were one gathers and analyses existing data or historical records to identify patterns
What are correlational studies?
Include many types of research such as observational or archival, but simply look for potential relationships between variables
What are two types of correlational studies?
Observational or archival
What type of studies gather information to determine the strength and direction of an association?
Correlational studies
What is defines the strength and direction of an association?
Correlation coefficient
Does correlation imply causation?
Correlation does NOT imply causation
What are case studies?
Detailed investigations of an individual, group or event
What are two types of case studies?
Prospective and retrospective
What are prospective case studies?
A case is observed in order to determine a possible outcome
What is a retrospective case study?
A case’s history is thoroughly analysed in order to determine a particular sequence of events
In general, are case studies representative of the population?
No, they tend to focus on detailed, qualitative information of rare occurrences
What is cross-sectional research?
Research that occurs at a single point in time and examines one variable between different groups that are similar in all other aspects
What is longitudinal research?
It involves collecting data at the beginning of the study and repeatedly throughout its duration
What are two types of statistics that psychologists and other scientists use together to make sense of their research?
Descriptive statistics
Inferential statistics
What are descriptive statistics?
Encompass the procedures used to describe a collection of information quantitatively
What are the three essential components of descriptive statistics?
1) measures of central tendency
2) measures of variability
3) measures of correlation
What are the three main measures of central tendency?
Mean, median, mode
What is the mean?
Arithmetic average
What are outliers?
Values that are unusually small or a large compare to the rest of the dataset
For a dataset that contains outliers, it is the best measure of central tendency to use?
The median
What is the median?
The middle value in a data set when all the values have been arranged in numerical order
What is the mode?
The most frequently occurring value
What are the three types of modes?
Unimodal, bimodal, or multimodal
Where are the important measures of variability?
Range, standard deviation, and normal distribution
What is the range?
The difference between the highest and lowest values
What is standard deviation? (SD, sigma)
Describes the degree to which a value varies from the average
What does a high standard deviation indicate?
Indicates that the data points are spread over a large range
What does a low standard deviation indicate?
The value points are spread over a small range and are located more closely to the average
What is the normal distribution?
A commonly occurring bell shaped probability distribution that describes the spread of data
What percentage of values are found within one standard deviation of the mean?
68%
What percentage of values are found within two standard deviations of the mean?
95%
What percentage of values are found within three standard deviations of the mean?
99.7%
What is the correlation coefficient (r)?
A statistical measure that indicates the strength and direction of a linear relationship between two variables
What is the range of correlation coefficient values?
+1 to -1
Positive values indicate what type of correlation coefficient?
Positive coefficient
What does a positive correlation mean?
As one variable increases, the other will increase as well
Negative values indicate what type of correlation coefficient?
Negative correlation
What is a negative correlation mean?
As one variable increases, the other will decrease
When r=+1, what is the term for the correlation coefficient?
Perfect and positive
When r=-1, what is the term for the correlation coefficient?
Perfect and negative
What does an r=0 value indicate about the values and correlation ?
The variables are totally independent of one another; there is no correlation
What do you descriptive statistics allow researchers to describe ?
Describe quantitatively the data they have collected
Can descriptive statistics apply to the rest of the population?
No, descriptive statistics apply only to the sample that was acquired and cannot be generalised to the population
What type of statistics allow researchers to determine how reliable and significant their data are?
Inferential statistics
What are the two major components of inferential statistics?
Statistical significance and statistical power
If an experiment or study has statistical significance, what does this mean?
There is an excepted little low probability that the results occurred due to chance
the boundary between statistical significance and the insignificance is based on a_______.
Pre-specified significance level (alpha level)
What does the Alpha level indicate the probability of?
Committing a type 1 error
What is a type 1 error?
Rejecting the null hypothesis when it is actually true
What is the most commonly used alpha level? What does this mean?
Alpha= 0.05; means that over time, a true null hypothesis will be wrong fully rejected one out of every 20 times
As the Alpha level become smaller, the test for significance becomes……
More stringent
Once an alpha level has been set researchers obtain what value?
P value
What is the P – value?
The value that describes the likelihood of observing a particular outcome due to chance, given for the data’s distribution
What happens if a P value is less than or equal to the Alpha level?
We reject the null hypothesis
What does it mean to reject the null hypothesis?
Our results are statistically significant
What happens if the P value is greater than the alpha level?
We fail to reject the null hypothesis
If we reject our null hypothesis, does this mean we accept our alternative hypothesis?
No, our results only support the alternative hypothesis
If we fail to reject the no hypothesis what does this mean about our results?
Our results are statistically insignificant
What does statistical power reveal?
Reveals how large the sample needs to be to ensure that statistical tests, such as determining statistical significance, are both accurate and reliable
According to statistical power, what happens if the sample size is too small?
Any results will not be precise enough to yield any meaningful information
What happens if the sample size is larger than required?
Statistical tests become more accurate and reliable
What is another term for statistical power?
Sensitivity
What does statistical power represent?
The probability that a statistical test, such as determining the statistical significance, will correctly reject the null hypothesis
What does statistical power try to avoid committing?
Type II error (beta)
What is a type II error?
Failing to reject the null hypothesis when it is actually false
