Mrs H 3 stats

Question 1

when should the chi-squared test be used?

Answer 1

frequencies for different categories (e.g. colour) and the categories don’t have a particular order (like size). Each person (or animal or plant) only appears in your results once and results don’t interfere with each other (are independent)

Question 2

when should Spearman’s rank correlation coefficient be used?

Answer 2

allows to work out the degree to which the two sets of continuous data are correlated. Involves ranking variables in size order so can only be used when both variables can be put in size oder

Question 3

when should the student’s t-test be used?

Answer 3

data must be in two categorical groups, e.g. ‘treated’ and ‘untreated’ but don’t have to be the same group sizes. it needs to be from different individuals and should be interval data (measured on a scale where each unit is the same size e.g. length in centimetres)