W5 - T-tests

Question 1

What are the assumptions of a paired t-test

Answer 1

Data is continuous/scale (interval or ratio)

Differences are normally distributed

No significant outliers in the ‘differences’

Question 2

What is the degrees of freedom?

Answer 2

No. of observations that are free to vary in any calculation of the mean.

Question 3

What is the degrees of freedom for a paired t-test

Answer 3

(n-1)

Question 4

What is the degrees of freedom for an independent t-test

Answer 4

(n-2)

Question 5

What happens if our t-statistic (i.e 5.417) is further away from 0 than the critical ‘t’ value (i.e 2.262)?

Answer 5

We REJECT the null hypothesis

Question 6

What are the assumptions of an independent t-test

Answer 6

Data is on a continuous scale + normally distributed

Normality of DV in each group.

Homogeneity of variance

Question 7

What does the levene’s test tell you?

Answer 7

Tests the null hypothesis in questioning whether the population variances are equal = homogeneity of variance

Question 8

What can squaring the SD from the SPSS output give you?

Answer 8

SD^2 = variance