RESEARCH METHODS- types of statistical test

Question 1

What is nominal, ordinal and interval data?

Answer 1

Nominal: Tallies of discrete categories
Ordinal: Whole numbers that can be ordered, but are not necessarily precise measurements
Interval: Standardised units of measurement (that can include a decimal point)

Question 2

Inferential testing table.

Answer 2

Test of difference Test of correlation
Unrelated Related
Nominal Chi squared Sign test Chi squared
Ordinal Mann Whitney Wilcoxon Spearman’s rho
Interval Unrelated t test Related t test Pearson’s r

Question 3

What is the sign test?

Answer 3

The sign test is a way to calculate the statistical significance of differences between related pairs (e.g. before and after in a repeated measures experiment) of nominal data. If the observed value (s) is equal or less than the critical value (cv), the results are statistically significant.

Question 4

How do you do the sign test?

Answer 4

The most important thing in the sign test is not the actual amount (e.g. 4, 6, etc.), but the sign.
Look to see if your experimental hypothesis is two-tailed (i.e. a change is expected in either direction) or one-tailed (i.e. change is expected to go in one direction).
Find out the p value for the example (this will be provided in the exam).
Using the information above, look up your critical value (cv) in a critical values table (this will be provided in the exam).
Work out the observed value (s) by counting the number of instances of the less frequently occurring sign.