✓ Inferential Statistics - choosing a statistical test (AO1)

Question 1

What is step 1 of choosing a statistical test?

Answer 1

Test of Difference or Correlation

Question 2

How do you know if its a test of difference or a correlation?

Answer 2

test of difference = is the test looking for a difference between 2 conditions?
(e.g. between gender/IQ)

correlation = is the test looking for a correlational relationship between 2 variables?
(e.g. between sunshine & happiness)

Question 3

What is step 2 of choosing a statistical test?

Answer 3

Independent or Repeated Measures

Question 4

How do you know if its an independent or repeated measures?

Answer 4

independent measures = ppts in each condition are different

repeated measures = the same ppts are used in both conditions of the experiment (incl. matched pairs)

Question 5

What is step 3 of choosing a statistical test?

Answer 5

Level of Data
- nominal
- ordinal
- interval/ratio

Question 6

How do you know if the data is nominal/ordinal/interval?

Answer 6

nominal = represented in the form of categories
(e.g. what is your fav colour? - red, green, blue)

ordinal = data that can be put in order, doesn’t have equal intervals between each unit, often based on subjective opinion
(e.g. on a scale of 1-10 how much do you like psychology?)

interval/ratio = based on numerical scales that incl. units of equal & precisely defined size - it is the most precise & sophisticated form of data
(e.g. time, weight, temp)

Question 7

What is the order of the statistical test table?

Answer 7

“carrots should come mashed with swede under roast potatoes”

left hand side = NOI
top = IR (test of difference) R (correlation)

chi square, sign test, chi square
mann whitney, wilcoxon, spearman’s rho
unrelated t-test, related t-test, pearson’s r