Week 9 Statistical inference and effect sizes

Question 1

What do you do if p>0.05?

Answer 1

Fail to reject the null hypothesis

Question 2

What do you need to get a significant effect when the real effect is very small?

Answer 2

A very large sample

Question 3

What are the key sections in a report?

Answer 3

Background
Methods (if you have been given them)
Results
Conclusion

Question 4

In a report what goes into your background?

Answer 4

What is the study looking at?

What is your hypothesis (null and alternative)

Question 5

What should the methods include?

Answer 5

Number and information of participants.
What they are doing
Tests used (analysis)
Assumptions needed plus what you used to test for the assumptions

Question 6

What do you need to include in the results?

Answer 6

The assumption of normality was met
Mean values and SD
Mean difference and CI
T-test values

Question 7

What do you say in your conclusion?

Answer 7

The main finding of the study
Whether you reject or fail to reject the null hypothesis
A basic summary saying what the finding mean

Question 8

What is effect size?

Answer 8

An objective and standardised measure of the magnitude of an observed effect.
Basically how significant an effect is

Question 9

What are the measures of effect size?

Answer 9

Cohen’s d
Glass’ g
Pearson’s correlation coefficient (r)

Question 10

If the effect size is r=0.10 what is the size if the effect?

Answer 10

Small, 1% of variance

Question 11

If the effect size is r=0.30 what is the size if the effect?

Answer 11

Medium, 9% of variance

Question 12

If the effect size is r=0.50 what is the size if the effect?

Answer 12

Large, 25% of variance