Introduction to A2 research methods:

We will look at the following concepts in a nut shell:

• Inferential tests & Significance • Null hypothesis

Inferential testsThese are tests that are carried out to test the statistical significance of the results.

The tests you need to know are called: • Mann Whitney • Wilcoxin• Spearmans Rho • Chi-Square test

These tests give you a ‘calculated value’ which is then compared to a ‘critical value’ (this is provided in a Psychology stats book). Based on this you can see if your results are significant and whether you should accept or reject your hypotheses

You need to know certain information to know which test to carry out, we will look at this

next year (see next slide)

Test of difference or correlation

Spearman’s Rho

Mann-Whitney U testWilcoxon T

Chi Square

At ordinal levelNominal or at least ordinal level data?

Independent groups design

Repeated measures/matched pairs or independent groups design?

Null hypothesis

Effectively in Psychology when we analyse the data we are trying to find out if our null hypothesis can be supported or not.

Null hypothesis • A null hypothesis for an experiment states

there will be NO difference• A null hypothesis for a correlation states there

will be NO correlation.

Project: Results section (analysis of data)

Pages 6 & 7 in packs:• Descriptive stats:

– Mean and range – What do the descriptive stats show?– Graph

• Inferential stats: – Conduct your inferential test online

• Google the name of test.• Input raw scores.• Write down the critical value given and whether your result is significant.• Write down whether you need to support or reject your alternative

hypothesis.

– Write conclusion based on this.