research methods: statistical testing-> the sign test Flashcards
What is the sign test?
A statistical test used by psychologists to work out if the data they have collected is in fact significant by analysing the difference in scores between related items
What are the three criteria for the sign test?
- Experiment must be a repeated measures design
- Experiment must measure a difference between two conditions
- collected data that can be organised into categories - known as nominal data
What word describes a p value that is lower than 0.05?
stringent
What is the first step of the sign test?
1) State the hypothesis
What is the second step of the sign test?
2) Convert the data to nominal data
- first data - second data = sign difference
What is nominal data?
Data that shows how often something happens (frequency data)
What is step 3 of the sign test?
3) Count up the number of signs
- count up the number of pluses and minuses from the nominal column
What is step 4 of the sign test?
4) Calculate the value of s
- to calculate s take the least frequent sign (known as S or the calculated value)
What is step 5 of the sign test?
5) Use the statistical table to find the critical value
- the number that tells us to reject or accept the hypothesis
What information is required to use the table?
- The significance level (usually 0.05)
- The number of participants in the investigation (N value/df)
- Whether the hypothesis is directional or non-directional
What is step 6 of the sign test?
6) Compare the calculated value to the critical value
- S must be less than or equal to the critical value for the results to be significant
What is step 7 of the sign test?
7) Write a conclusion, state:
- Whether the results are significant
- Whether you accept or reject the hypothesis
