Y13 RESEARCH METHODS - PARAMETRIC: unrelated and related t tests

Question 1

what is an unrelated t-test?

Answer 1

test of difference between two sets of data
used with interval level data only
independent groups design
ps are drawn from a normally distributed population

Question 2

step 1 of unrelated t-test?

Answer 2

table of data =
-calculate sum of scores for group A and B
- square each value in both groups and work out the sum of the squared values

Question 3

step 2 of unrelated t-test?

Answer 3

work out the value of t using the equation

Question 4

step 3 of unrelated t-test?

Answer 4

calculated value > critical = significant difference

Question 5

what is a related t-test?

Answer 5

• done when a repeated measures design is used
• ps drawn from a normally distributed population
• interval data
• homogeneity of variance between the two data sets

Question 6

step 1 of related t test?

Answer 6

the table of data =

calculate difference between condition A and B
square each difference
sum of all the d values
sum of all d^2 values

Question 7

step 2 of related t test?

Answer 7

work out value of t using the equation

Question 8

step 3 of related t test?

Answer 8

calculated value > critical value = significant difference

Question 9

how do you work out the df in a related t-test?

Answer 9

N - 1

Question 10

how do you work out the df in an unrelated t-test?

Answer 10

Na+ Nb - 2