Flashcards in Scientific Investigation Deck (33):

1

## What are the 5 steps of scientific investigation?

###
Per Kazdin (2003):

Formulate a testable hypothesis

Select a research method and design the study

Collect the data

Analyze the data

Report the findings

2

## What is a hypothesis?

### A tentative statement about the relationship between variables

3

## What is the null hypothesis?

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

4

## What is the alternate hypothesis?

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

5

## What is the independent variable (IV)?

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

6

## What is the dependent variable (DV)?

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

7

##
What is a true experiment?

(Kazdin, 2003)

###
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

8

##
What is a quasi-experimental design?

Per Kazdin, 2003

###
Conditions of the experiment are approximated

Restrictions are placed on some aspect of the design

9

## What is statistical significance?

###
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

10

## How is statistical significance indicated?

###
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

11

## What is a Type I error?

###
Rejecting a true null hypothesis

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

12

## What is statistical power?

###
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

13

##
What is power analysis?

(Kazdin, 2003)

###
A way of deriving at the ideal sample size number

Increase power by increasing the sample size

14

##
What are the 4 concepts involved in increasing power?

(Kazdin, 2003)

###
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**

15

## What are the common factors of effect size?

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

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

16

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

(Ruderstram and Newton, 1992)

###
Interview

Physiological data

Psychological report

Archival data

Direct observation

17

## What is Type II error?

###
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

18

## What is an effect size?

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

19

## What is the correlation coefficients?

###
used to analyze the relationship between two variables

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

20

## What is an effectiveness study?

### applies to actual patients, the actual population

21

## What is an efficacy study?

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

22

## What is between groups?

### looking at differences between different groups

23

## What is within groups?

###
looking at differences within

looking at the same person over time

24

## What is a main effect?

### the overall effect of one independent variable

25

## What is the interaction effect?

###
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

26

## What is a moderator?

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

27

## What is a mediator?

### variable that explains the relationships between two other variables

28

## What is a confounding variable?

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

29

## What is the citation for scientific investigation?

### Kazdin, 2003

30

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

### Ruderstram and Newton, 1992

31

## What is indicated by predictor?

### Regression

32

## What is indicated by relationship?

### Correlation

33