Repeated Measures Design and Correlations

Question 1

What is a repeated measures design?

Answer 1

Participants are tested in 2 conditions (or more)

Question 2

What are the advantages of repeated measures designs?

Answer 2

> Fewer participants are needed to run an experiment as compared to a between-groups design
This can save material, money and effort
Less error in your experiment than there would be if you had 2 separate groups

Question 3

Disadvantage of repeated measures designs?

Answer 3

Practice/ Order effects

Question 4

what factors can practice effects occur due to?

Answer 4

A number of different factors e.g. learning, fatigue, adaptation, habituation, sensitisation, contrast etc.

Question 5

How do we combat practice/order effects?

Answer 5

COUNTERBALANCING

Question 6

What is counterbalancing?

Answer 6

This means assigning participants to different conditions in different orders.

Question 7

What is complete counterbalancing?

Answer 7

Takes into account every possible combination e.g. 123, 231, 312.

Question 8

when does complete counterbalancing become more difficult?

Answer 8

when you have lots of different conditions- lots of different combinations.

Question 9

What is partial counterbalancing?

Answer 9

randomly aelecting a sub set of possible conditions orders and assigning participants randomly to those.

Question 10

One type of ______ design is called a correlational design.

Answer 10

Repeated measures

Question 11

How many variables will a correlational design have?

Answer 11

2

Question 12

What scales can variables be on in a correlational design?

Answer 12

either ordinal, interval or ratio.

Question 13

What study design is this?

Increasing self harm is associated with lower self esteem.

Answer 13

Correlational design

Question 14

A correlation is a description about how…

Answer 14

2 variable are associated with one another

Question 15

name the 2 types of correlation.

Answer 15

Positive and Negative.

Question 16

name this correlation type:

As one variable increases so does the other.

Answer 16

Positive :)

Question 17

name this correlation type:

As one variable increases, the other decreases.

Answer 17

negative.

Question 18

What is the descriptive statistic for a correlation?

Answer 18

A scatterplot :)

Question 19

If you have an IV and a DV, what axis should the IV be on in a scatter plot?

Answer 19

The x-axis.

Question 20

what can we draw to help us see a potentially significant trend on the scatter plot?

Answer 20

A line of best fit

Question 21

What can the line of best fit show us?

Answer 21

A potentially sig relationship between 2 variables.

Also helps identifying outliers.

Question 22

If correlation = 0 what does this mean?

Answer 22

There’s no correlation.

Question 23

If correlation = -1 what does this mean?

Answer 23

Strong negative correlation

Question 24

If correlation = +1 what does this mean?

Answer 24

Strong positive correlation

Question 25

the stronger the correlation, the ____ the dots to the line of best fit.

Answer 25

closer

Question 26

what does r stand for?

Answer 26

correlation :)

Question 27

what is the strongest correlation you can get?

Answer 27

r= 1 OR r = -1

Question 28

What does r = 0 mean?

Answer 28

No linear relationship

Question 29

If there is no linear relationship what should we consider?

Answer 29

There might still be a non-linear relationship e.g. increase then decrease.

Question 30

What is an outlier?

Answer 30

A really unusual score

Question 31

There are 2 options re- what we do with our outliers?

Answer 31

delete it OR keep it and report the fact there is outliers.

Question 32

It's probably best to do what with outliers?

Answer 32

delete them

Question 33

You can use a scatterplot to identify outliers, but what else could you use?

Answer 33

SPSS

Question 34

How do we identify outliers on SPSS?

Answer 34

If they are greater than or less than 3.29.

Question 35

Any significant correlation has a number of interpretations- what are these?

Answer 35

1. We made a type I error 2. Changes in A caused change in variable B 3. Changes in B caused change in variable A 4. Both changes in variables A and B influence each other 5. the 3rd variable problem- and omitted variable C accounts for the link between A and B!

Question 36

Remember correlation is not ________.

Answer 36

causation

Question 37

don't say A causes B- what should we say instead?

Answer 37

There's a sig. relationship between A and B

Question 38

What visually represents our correlation?

Answer 38

scatterplot

Question 39

what is the coefficient determination?

Answer 39

literally jus the correlation multiplied by itself e.g. r squared.

Question 40

Caleculate the effect size: | r= .5

Answer 40

r squared = .25

Question 41

What does an effect size of .25 tell us?

Answer 41

25% of the variation in A can be accounted for by variation in B (or vice- versa).

Question 42

The left over percentage from the effect size .25 means what?

Answer 42

means that 75% of variation is due to random error and other things we haven't measured.

Question 43

If effect size = 1 we could perfectly predict the …… | we couldn't predict it at all of effect size was ___.

Answer 43

second variable | 0

Question 44

what is a small effect size?

Answer 44

r2 = .01 to .08

Question 45

what is a medium effect size?

Answer 45

r2 = .09 to .24

Question 46

what is a large effect?

Answer 46

r2= .25 and above.

Question 47

What do parametric tests assume about your data?

Answer 47

> interval or ratio data >normally distributed- not skewed. > at least 10 participants on each level of you dependent variable.

Question 48

What is the parametric test for correlations?

Answer 48

Pearson Correlation Coefficient | aka. Pearsons

Question 49

What is the non-parametric test for correlations?

Answer 49

Spearman Rank Order Correlation | aka. Spearman's Rho

Question 50

What is a one tailed hypothesis?

Answer 50

It states the direction of the correlation i.e. "there will be a significant positive correlation between..."

Question 51

What is a 2 tailed hypothesis?

Answer 51

It doesn't give a direction- it just says "there is a significant correlation between the 2 variables"

Question 52

Pearson’s correlation revealed a significant, ______ correlation between self esteem and depression, r = -.88, n=54, p=.020. What is the effect size?

Answer 52

negative | effect size = r2= .77

Question 53

The alternative hypothesis takes 2 different forms, what are they?

Answer 53

1 tailed and 2 tailed.

Question 54

in a 2 tailed hypothesis, what happens to the 5%?

Answer 54

It's split 2.5% either side.

Question 55

In a 1 tailed hypothesis, what happens to the 5%?

Answer 55

The 5% is all to the one side.

Question 56

What is good about a 1 tailed?

Answer 56

Greater chance of accepting something as significant IF it's in the direction you accepted.

Question 57

what data does Spearman's Rho require?

Answer 57

at least ordinal

Question 58

Rs stands for....

Answer 58

Spearman's Rho

Question 59

R s = .94, n=10, p=

Answer 59

NOTHING- no effect size reported in Sperman's Rho.

Question 60

What are the 2 ways to report p values?

Answer 60

p = .xxx OR P < .001

Question 61

How many dp is p reported to?

Answer 61

3!

Question 62

Correlation can be used to establish ____ reliability.

Answer 62

test

Question 63

What is this called?: Do same test to same sample of participants at 2 different times e.g. 1 week apart. Then correlate their scores on two sets of responses, if it’s a reliable measure then the 2 sets of scores should be highly correlated (>.70). Reported using standard format as a normal correlation (no need for effect size).

Answer 63

Test reliability

Question 64

What is split half reliability?

Answer 64

Add up scores from half test items. Add up other half. Both scores are then correlated, if both halves are measuring the same construct they should be highly correlated (> 0.70). rsb = .78 is how it’s reported.

Question 65

What is internal reliability also known as?

Answer 65

Cronbach's alpha

Question 66

____ _____ represents the average degree to which each item is correlated with all other items.

Answer 66

Cronbach's Alpha

Question 67

What should Cronbach's alpha be above to indicate a reliable scale?

Answer 67

.70

Question 68

What does Cronbach's alpha test?

Answer 68

Basically of all items on the scale are measuring the same thing.