17. Statistical Testing AO1

Question 1

What are the 4 categories or statistical testing?

Answer 1

• Significance
• Probability
• Calculated/critical values
• Finding critical value

Question 2

What is significance?

Answer 2

The difference/association between two sets of data is greater than what would occur by chance

Question 3

What is probability?

Answer 3

• A numerical measure of the likelihood that certain events will occur
• The level at which the researcher decides to accept the research hypothesis or not

Question 4

What is the accepted level of probability in psychology?

Answer 4

0.05 (5%)

Question 5

What happens if the hypothesis is accepted?

Answer 5

There is less than 5% probability that the results occurred by chance

Question 6

Outline calculated and critical values

Answer 6

• The calculated value is compared with a critical value to decide whether the result is significant or not
• the critical values for a particular test are given in a table of critical values

Question 7

What are the three pieces of information needed for finding the critical value?

Answer 7

1. The significance level (0.05/5%)
2. Number of participants or degrees of freedom
3. Whether hypothesis is directional or non-directional

Question 8

When is a sign test used?

Answer 8

To analyse the difference in scores between related items, e.g. same participant tested twice

Question 9

Outline how a sign test is calculated

Answer 9

1. Score for condition B subtracted from A to produce sign difference (- or +)
2. Total pluses and total minuses are calculated
3. Participants ho achieved same score in A and A are disregarded, and deducted
4. S value is total of the less frequent