week 9

Question 1

How to chose which test

Answer 1

type of data
Normality
Homogeneity of variance
Independence

Question 2

How to test normality

Answer 2

plot the data
look at Q-Q plots
use a statistical test to compare your distribution to normality

Question 3

How to calculate homogeneity of variance

Answer 3

For comparing independent groups
We can use Levene’s test: If p<.05 then we can reject this and assume the variance is not the same

Question 4

What are the type of types for independent groups

Answer 4

independent sample t-test and Mann-Whitney U test

Question 5

What are the independent t-test

Answer 5

t= observed difference between sample means/ estimate of the standard error between means

The principle of the independent t-test is the same as the paired t-test

Question 6

When would we use the Mann-Whitney U

Answer 6

when it doesn’t meet the non-parametric model

Question 7

What is the Mann-Whitney U

Answer 7

the non-parametric equivalent for the independent sample t-test

Question 8

What is the sample size

Answer 8

as the sample size increase, the distribution becomes more like a normal distribution
Sample size can’t be too small but is more difficult to meet the assumption if the sample is too small so we may in thi9s case do individual-level statistics might be appropriate