stats research methods Flashcards
A sociologist proposes that the reason why people living below the poverty level have worse outcomes even for relatively minor health problems is because they have little or no access to adequate healthcare. In this situation, lack of access to healthcare is a(n) __________ variable.
A. moderator
B. mediator
C. control
D. outcome
B. mediator
Psychology 101 students are assigned ranks based on their total scores on a 50-item midterm exam. The ranks represent a(n) _____ scale of measurement.
A. nominal
B. interval
C. ratio
D. ordinal
D. ordinal
The mode, median, and mean for a distribution of final exam scores are 75, 50, and 35, respectively. Based on this information, you can conclude that this distribution is:
A. positively skewed.
B. negatively skewed.
C. leptokurtic.
D. platykurtic.
B. negatively skewed.
A school psychologist designs a study to determine if student gender and grade level are related to the number of interactions male and female teachers have with their students. This study has ___ independent variables and ___ dependent variable(s).
A. 2; 1
B. 2; 2
C. 3; 1
D. 3; 2
C. 3; 1
A distribution of scores has a mean of 60 and standard deviation of 5 and scores are normally distributed. Based on this information, you can conclude that about ___% of scores fall between the scores of 50 and 70.
A. 50
B. 68
C. 95
D. 99
C. 95
What is an independent vs dependent variable?
An independent variable is the variable that a researcher believes has an effect on the dependent variable.
What is a mediator vs moderator variable?
-affect the relationship between the study’s independent and dependent variables and make it difficult to determine if an apparent effect of an independent variable on a dependent variable is actually due to the independent variable.
-Mediator variable explains the relationship between independent and dependent variables. For instance, cognitive therapies are based on the assumption that therapy reduces anxiety because it alters client’s dysfunctional thinking. In other words, therapy (the independent variable) leads to more realistic thinking (mediator variable) which, in turn, leads to reduced anxiety (dependent variable).
What is an extraneous variable?
Affect the relationship between the study’s independent and dependent variables and make it difficult to determine if an apparent effect of an independent variable on a dependent variable is actually due to the independent variable.
What is nominal scale?
-divide people into unordered categories. Gender, eye color, and DSM diagnosis are nominal variables. Numbers can be assigned to the categories, but they’re just labels and do not provide any quantitative information.
1. qualitative
2. names, color, labels, etc.
3. order does not matter.
What is interval scale?
Variables measured on an ordinal scale divide people into categories that are ordered in terms of magnitude. (for example the WISC)
1. the order matters
2. differences dan be measured (except ratios)
3. not true 0 starting point.
What is ratio scale?
- the order matters
- differences dan be measured.
- contains a true 0 starting point.
what bar graphs are used for what?
bargraphs for nominal and ordinal
one dimensional
histograms for interval and ratio
two dimensional
frequency polygon(line graph) interval and ratio data
explain stardard deviation in a norm distribution
68 percent in 1 standard deviation—16-84
2 standard deviation is 4 to 95
3 standard deviation is 99 percent
positive and negatively skewed in terms of distribution of mode, medium and mean?
positive it goes mean median and mode
negative is goes mode, median, mean
lepokurtic and platykurtic peaks?
A leptokurtic distribution has a sharper peak and flatter tails than a normal distribution (i.e., most scores are “piled up” in the middle of the distribution). In contrast, a platykurtic distribution is flatter in the middle and has thicker tails than a normal distribution
——think plat means flat
Explain internal vs external validity?
Internal is to the study.
external is an application or generalization outside the study.
types of external validity?
population
ecological
temporal is generalizability of results over time
treatment
outcome is the generalizability of results to different but related dependent variables.
Threats to internal validity what does this mean?
it means factors of variable that could compromise the internal validity of the study?
Threat to internal validity History explain?
History refers to events that occur during the course of a study and are not part of the study but affect its results.
—-e.g. a power outage
Threat to internal validity maturation explain?
Maturation refers to physical, cognitive, and emotional changes that occur within subjects during the course of the study that are due to the passage of time and affect the study’s results
Threat to internal validity differential selection explain?
It occurs when groups differ at the beginning of the study due to the way they were assigned to groups and this difference affects the study’s results.
Threat to internal validity statistical regression explain?
threatens a study’s internal validity when participants are selected for inclusion in the study because of their extreme scores on a pretest. It occurs because many characteristics are not entirely stable over time and many measuring instruments are not perfectly reliable
Threat to internal validity testing explain?
Testing threatens a study’s internal validity when taking a pretest affects how participants respond to the posttest.
Threat to internal validity instrumentation explain?
when the instrument used to measure the dependent variable changes over time. For example, raters may become more accurate at rating participants over the course of the study.
Threat to internal validity differential attrition explain?
threatens internal validity when participants drop out of one group for different reasons than participants in other groups do and, as a result, the composition of the group is altered in a way that affects the results of the study
Threats to External Validity: reactivity
whenever participants respond differently to the independent variable during a study than they would normally respond. Factors that contribute to reactivity include demand characteristics and experimenter expectancy. Demand characteristics are cues that inform participants of what behavior is expected of them. Experimenter expectancy occurs when the experimenter acts in ways that bias the results of the study and can involve
Threats to External Validity:multiple treatment interference
Multiple treatment interference is also referred to as carryover effects and order effects. It may occur whenever a within-subjects research design is used – i.e., when each participant receives more than one level of the independent variable. For example, if a low dose, moderate dose, and high dose of a drug are sequentially administered to a group of participants and the high dose is most effective, its superior effect may be due to the fact that it was administered after the low and moderate doses. Multiple treatment interference is controlled by using counterbalancing, which involves having different groups of participants receive the different levels of the independent variable in a different order.
A researcher conducted a study to assess the effects of cognitive behavior therapy for treating depression in adolescents by comparing it to nondirective supportive therapy. Fifty adolescents who recently received a diagnosis of major depressive disorder were randomly assigned to one of the two therapies. Each participant’s level of depression was assessed at the beginning of treatment and one month after treatment ended. The results indicated that adolescents in both groups improved to the same degree in terms of depressive symptoms. Which of the following is the biggest threat to this study’s internal validity?
A. differential selection
B. reactivity
C. maturation
D. instrumentation
C. maturation
Threats to External Validity:selection treatment interference
when research participants differ from individuals in the population, and the difference affects how participants respond to the independent variable
Threats to External Validity: pretest-treatment interaction
when taking a pretest affects how participants respond to the independent variable
-Solomon four-group design is used to identify the effects of pretesting on a study’s internal and external validity.
Counterbalancing is most useful for controlling which of the following threats to external validity?
A. reactivity
B. selection-treatment interaction
C. multiple treatment interference
D. pretest sensitization
C. multiple treatment interference
To evaluate a brief intervention for improving the social skills of adolescents with autism spectrum disorder, a researcher administers a measure of social skills to a sample of adolescents with this diagnosis, chooses the adolescents with the lowest scores on this measure to participate in the intervention, and then re-administers the measure of social skills one week after the adolescents have participated in the intervention. The biggest threat to the internal validity of this study is:
A. instrumentation.
B. reactivity.
C. pretest sensitization.
D. statistical regression.
D. statistical regression.
The Solomon four-group design is used to:
A. evaluate the effects of pretesting.
B. reduce the effects of multiple treatment interference.
C. ensure that groups are similar at the beginning of the study.
D. reduce experimenter expectancy effects.
A. evaluate the effects of pretesting.
The best way to reduce the effects of differential selection on the results of a research study is to:
A. randomly select subjects from the population.
B. randomly assign subjects to the treatment groups.
C. use the single-blind technique.
D. use the double-blind technique.
B. randomly assign subjects to the treatment groups.
qualitative research approach grounded theory?
to derive a general, abstract theory of a process, action, or interaction grounded in the views of the participants in a study” The primary data collection methods are interviews and observations.
what is phenomenology qualitative research?
To derive and understanding of the lived experiences of the participants.
Interviews are the best.
what is ethnography research?
studying participants in their natural culture or setting
What is thematic analysis?
s a method for identifying, analyzing, and reporting patterns (themes) within the data” focus groups and in depth interviews
What is qualitative research triangulation?
triangulation “is the research practice of comparing and combining different sources of evidence in order to reach a better understanding of the research topic”
Methodological triangulation?
using multiple methods to obtain data
data triangulation?
using the same method to obtain data at different times
investor triangulation?
multiple investigators to collect and analyze data?
theory triangulation?
interpreting or analyzing data from multiple theories?
type of quantitative research descriptive?
measure and describe a set of variables as they occur naturally
type of quantitative research correlational?
two or more variables to determine the magnitude and direction of the relationship between the variables