L8 (week 9)- Mann-whitney & Levene's test

Question 1

What is the difference between an independent t-test and a paired t-test?

what are you comparing? what samples?

Answer 1

For an independent t-test you are comparing the means of 2 independent samples, For at paired t-test you are comparing the means of 2 related samples.

Question 2

What does the Mann-Whitney U test do?

Order of data

Answer 2

Ranks sums and group sizes to calculate the test statistic.

Question 3

How do we work out the test statistic (t) in an independent t-test?

divide difference between BLANK by the estimate of the BLANK between BLANK

Answer 3

Divide the observed difference between sample means by the estimate of the standard error between means.

Question 4

what is the sum to workout effect size (r) for a non-parametric test?

Pearsons R calculation

Answer 4

The test statistic (z) divided by the square root of how many participants data was used. (r = Z/√N)

Question 5

what is the purpose of the levene’s test?

Checks EV of DV is BLANK

Answer 5

It checks whether the error variance of the dependent variable is the same across the groups.

Question 6

How do you run the Levene’s test is SPSS?

trick

Answer 6

It is automatically generated when you run and independent t-test.

Question 7

what are the two tests of normality called?

KS + SW

Answer 7

Kolmogorov-Smirnov and Shapiro-Wilk

Question 8

Which test of normality would you use for a group size of 30 or less?

KS OR SW

Answer 8

Shapiro-Wilks test