Week 2 - T-tests

Question 1

What are T-Tests used for?

Answer 1

Differences between groups (e.g. two experimental conditions)

Question 2

What are the IV and DV in a T-Tests?

Answer 2

CATEGORICAL IV: the things we are manipluating/varying/changing…

• e.g. men/women, old/young, colour/grey-scale, drug/placebo

CONTINUOUS DV (interval/ratio): the thing we are measuring, the outcome…

• e.g. height, heart rate, number of errors made, time, temperature

Question 3

Two types of design:

Answer 3

Independent samples / between subjects / independent groups design (Two different groups of participants)

Paired-samples / within-subjects / repeated measures design (One group of participants)

Question 4

Which test should i run?

Answer 4

Between subjects design, participants take part in a single condition:
- Data is normally distributed = INDEPENDENT samples t-test
- Data is NOT normally distributed = Mann-Whitney U

Within-subjects design particpants take part in BOTH conditions:
- Data is normally distributed: PAIRED samples t-test
- data is NOT normally distributed: Wilcoxon W