Sign test

Statistical testing

Provides a way of determining whether hypotheses should be accepted or rejected. By using a statistical test, we can find out whether differences or relationships between variables are significant (meaningful) or are likely to have occurred by chance

Whats a sign test

A statistical test used to analyse the difference in scored between related items (e.g the same participant tested twice ) data should be nominal

What are the conditions for the sign test

We need to be looking for a difference rather than an association

We need to have used a repeated measures design

We need data organised into categories ( nominal data)

Whats the critical value

When stat test calculated, researcher left with number (the calculated value). This needs to be compared to critical value to decide wether result is significant or not.

What info is needed to use critical value table

The significance level (5% / 0.05)

The number of participants in investigation (N value or sometimes degrees of freedom df)

Whether the hypothesis is directional (one tailed) or non directional (two tailed test)

give example for sign test steps

for energy drink example