Scientific Investigation

Question 1

What are the 5 steps of scientific investigation?

Answer 1

Per Kazdin (2003):
Formulate a testable hypothesis
Select a research method and design the study
Collect the data
Analyze the data
Report the findings

Question 2

What is a hypothesis?

Answer 2

A tentative statement about the relationship between variables

Question 3

What is the null hypothesis?

Answer 3

The hypothesis that specifies that there is no difference between conditions or groups in the experiment on the dependent measures of interest

Question 4

What is the alternate hypothesis?

Answer 4

The hypothesis that specifies that there is a difference between conditions or groups in the experiment on the dependent measures of interest

Question 5

What is the independent variable (IV)?

Answer 5

The variable (construct, experimental manipulation, intervention, factor) that is manipulated in the study

Question 6

What is the dependent variable (DV)?

Answer 6

The measure designed to reflect the impact of the IV, experimental manipulation, or intervention

Question 7

What is a true experiment?

Kazdin, 2003

Answer 7

Must meet the following conditions:
Random assignment of participants
Maximum control of IVs/condition of interest
Can include alternate conditions (treatment, control)
Can control possible sources of bias within the experiment that permit the comparison of interest

Question 8

What is a quasi-experimental design?

Per Kazdin, 2003

Answer 8

Conditions of the experiment are approximated

Restrictions are placed on some aspect of the design

Question 9

What is statistical significance?

Answer 9

Per Kazdin (2003)
Criterion used to evaluate the extent to which the results of a study (differences between groups or changes within groups) are likely to be due to genuine rather than chance effects

Question 10

How is statistical significance indicated?

Answer 10

Called alpha
Norms for different fields exist - .05 typically used for educational/psychological research
This is the level of risk associated with rejecting the null hypothesis

Question 11

What is a Type I error?

Answer 11

Rejecting a true null hypothesis

concluding there is a significant difference when really there isn’t

Question 12

What is statistical power?

Answer 12

Per Kazdin (2003)
The probability of rejecting the null hypothesis (that there are no differences) when in fact the hypothesis is false
AKA: detecting a difference between groups when there is truly a difference
AKA: the extent to which an investigator can detect a difference when one exists

Question 13

What is power analysis?

Kazdin, 2003

Answer 13

A way of deriving at the ideal sample size number

Increase power by increasing the sample size

Question 14

What are the 4 concepts involved in increasing power?

Kazdin, 2003

Answer 14

Statistical significance - typically .05
Effect size - measures the strength of the relationships
Power - typically .8
Sample Size - calculated based on the other three (# of participants per # of groups)
Know 3 to determine the 4th

Question 15

What are the common factors of effect size?

Answer 15

Cohen (1998): .2 for small, .5 for medium, .8 for large

Common metrics include Cohen’s d, Pearson’s r, and eta-squared

Question 16

What are the types of data than can be included in research?

Ruderstram and Newton, 1992

Answer 16

Interview
Physiological data
Psychological report
Archival data
Direct observation

Question 17

What is Type II error?

Answer 17

failing to reject the null hypothesis when it is actually false
concluding there isn’t a statistically significant difference when there really is one that you didn’t find

Question 18

What is an effect size?

Answer 18

the relationship or association or difference that you have set out to investigate

Question 19

What is the correlation coefficients?

Answer 19

used to analyze the relationship between two variables

the size of the relationship between two variables on a standard scale (0-1)

Question 20

What is an effectiveness study?

Answer 20

applies to actual patients, the actual population

Question 21

What is an efficacy study?

Answer 21

applies to RCT, random sampling from the population, discreet TX

Question 22

What is between groups?

Answer 22

looking at differences between different groups

Question 23

What is within groups?

Answer 23

looking at differences within

looking at the same person over time

Question 24

What is a main effect?

Answer 24

the overall effect of one independent variable

Question 25

What is the interaction effect?

Answer 25

only found in factorial designs in which the 2+ IVs are crossed
occurs whenever the effect of one IV depends on the level of te other

Question 26

What is a moderator?

Answer 26

variable that influences the strength of a relationship between two other variables

Question 27

What is a mediator?

Answer 27

variable that explains the relationships between two other variables

Question 28

What is a confounding variable?

Answer 28

variable that is influencing both the DV and IV and is not accounted for

Question 29

What is the citation for scientific investigation?

Answer 29

Kazdin, 2003

Question 30

What is the citation for the types of data used in scientific investigation?

Answer 30

Ruderstram and Newton, 1992

Question 31

What is indicated by predictor?

Answer 31

Regression

Question 32

What is indicated by relationship?

Answer 32

Correlation

Question 33

What is indicated by adjusting?

Answer 33

Covariates