Flashcards in Week 7 Lecture Deck (27):

1

## What does correlational research do?

###
Quantifies the strength of the relationship between two or more variables.

Cross-sectional design in developmental research is differential research

Cross-Sectional and Longitudinal Research

Cross-sectional designs are faster:

Can test many age groups simultaneously.

But cohort effects can be a problem:

Defined as “shared life experiences of people of a given age that lead them to behave similarly to others their age and different from people of other ages”.

Longitudinal designs are essentially time-series designs.

Would prefer longitudinal designs, but…

2

## Can correlations be used for prediction?

### Yes.

3

## Can correlation prove a theory?

### No but it may negate it.

4

## Can correlations establish causation?

### No.

5

## What do differential research methods do?

### Compare two or more preexisting groups.

6

## What research is differential research similar to?

### Correlational and experimental research.

7

## What research is differential research conceptually similar to?

### Correlational research

8

## Why is differential research conceptually similar to correlational research?

### Variables measured, but not manipulated.

9

## Are cross-sectional designs faster?

###
Yes, because they can test many age groups simultaneously.

10

## Can cohort effects be a problem with cross-sectional designs?

### Yes, “shared life experiences of people of a given age that lead them to behave similarly to others their age and different from people of other ages”.

11

## What are longitudinal designs essentially...

### Time-series designs.

12

## What is preferable; longitudinal designs or cross-sectional designs?

### Longitudinal.

13

## Can correlational or differential research establish causation?

### No.

14

## Is correlational or differential a higher level of constraint?

### Differential.

15

## Why is differential a higher level of constraint than correlational?

###
The researcher can select the comparison group(s) to control at least some of the potential confounding variables, thus providing stronger evidence for a theory.

16

## When do we use the correlational method?

### When we are interested in knowing the strength of a relationship for predictive purposes. Often included to help interpret the primary findings of a study.

17

## When do we use differential research?

###
When the manipulation of an independent variable is impractical, impossible, or unethical.

18

## What is correlation coefficient?

### A statistic indicating the degree to which two variables are related to one another in a linear fashion.

19

## What is the key requirement for a correlational coefficient?

###
The key requirement being that we obtain scores on the two variables of interest for each participant.

20

## What is the most common correlation coefficient?

###
Pearson correlation coefficient, r, is the most common.

r ranges from -1 to +1.

21

## What does r (in the pearson correlation coefficient) range from?

### +1 to -1.

22

## What does the sign represent in the correlation coefficient?

### The direction; positive or negative.

23

## Can any relationship be portrayed graphically on an x and y axis?

### Any relationship between two variables can be portrayed graphically on an x and y axis.

24

## For each participant we can plot their combined x and y score and this equals a...

### Scatter plot

25

## What would a curvilinear relationship?

### Calculation an r value would give a score of 0; very misleading.

26

## What does p value provide us with?

### The p value provides us with a measure of reliability

27