parametric tests: unrelated and related t-tests

Question 1

when should you use the unrelated t-test?

Answer 1

• test of difference between two sets of data
• interval data
• independent groups design

Question 2

(UTT) step 1: the table of data

Answer 2

• calcualted sum of scores for group A
• repeat for group B
• square each value in group A
• repeat for group B

Question 3

(UTT) step 2: working out the value of t

Answer 3

super complicated equation sorry… assuming they’ll give it in the exam

Question 4

(UTT) step 3: calculated and critical values

Answer 4

• ignore negative signs when checking critical values table
• df = number of participants of both groups together - 2
• when calculaed value is more than the critical value, the result is significant and we reject the null hypothesis

Question 5

when do you use a related t-test?

Answer 5

• repeated measures design
• interval data
• looking for a difference

Question 6

(RTT) step 1: the table of data

Answer 6

• caluclate the difference between scores for condition A and B (d)
• square each difference (d²)
• add up the values in the d column to give the sum of d (∑d)
• add up the values in the d² column to give the sumn of d² (∑d²)

Question 7

(RTT) step 2: working out the value of t

Answer 7

another super complicated equation sorry!!

Question 8

(RTT) step 3: the calculated and critical values

Answer 8

• df = N - 1
• if the calculated value of t is greater than the critical value, the result is significant. we reject the null hypothesis