choosing a statistical test

Question 1

what are the three factors to decide which statistical test to use?

Answer 1

1) are we looking for a difference or correlation
2) experimental design (IG, RM or MP)
3) level of measurement (nominal, ordinal or interval data)

Question 2

what are the three types of experimental design?

Answer 2

independent groups, repeated measures, matched pairs

Question 3

what are the three levels of measurement?

Answer 3

nominal, ordinal and interval data

Question 4

define nominal data

Answer 4

data that’s represented in the form of categories and so is sometimes referred to as categorical data. Nominal data is discrete.

Question 5

define ordinal data

Answer 5

data is ordered in some way and it doesn’t have equal intervals between each unit. its subjective and so can be referred to asd unsafe data, because of this raw scores are converted into ranks.

Question 6

define interval data

Answer 6

based on numerical scales that include units of equal defined size. It’s the most precise form of data and so is used in parametric tests.

Question 7

which statistical test tests for a difference with an unrelated design using nominal data?

Answer 7

chi- squared

Question 8

which statistical test tests for difference, using a related design and nominal data?

Answer 8

sign test

Question 9

which statistical test tests for a correlation using nominal data?

Answer 9

chi- squared

Question 10

which statistical test tests for a difference with an unrelated design and ordinal data

Answer 10

mann-whitney

Question 11

which statistical test tests for a test of difference, using an unrelated design and interval data?

Answer 11

unrelated t-test

Question 12

which statistical test tests for a difference, using a related design and ordinal data?

Answer 12

Wilcoxon

Question 13

which statistical test tests for difference using a related design and interval data?

Answer 13

related t-test

Question 14

which statistical test tests for a correlation using ordinal data?

Answer 14

Spearman’s rho

Question 15

which statistical test tests for a correlation using interval data?

Answer 15

pearson’s r

Question 16

define the term independent groups

Answer 16

participants are allocated to different groups where each group represents one experimental condition

Question 17

define the term repeated measures

Answer 17

all participants take part in all conditions of an experiment

Question 18

define the term matched pairs

Answer 18

pairs of participants are first matched on some variables that may affect that dependant variable. one of the pair is assigned to condition A and the other to condition B

Question 19

define the term parametric test

Answer 19

parametric tests are more powerful and robust than other tests and they’re able to detect significance in some data sets that non-parametric tests cant.

Question 20

what are the three criteria that must be met in order to use a parametric test?

Answer 20

1) data must be interval
2) data should be drawn from a population that’s expected to show a normal distribution
3) there should be a homogeneity of variance