Probability and Significance

Question 1

What is the accepted significance level in psychology?

Answer 1

0.05% p= 0.05

Question 2

What happens when the results are significant at the 0.05% level?

Answer 2

We can reject the null hypothesis and accept the alternative

Question 3

When might the 0.01% significance level be used?

Answer 3

• Medical research

- If research is significant at 0.05% and you want to check for further significance

Question 4

What is the critical value?

Answer 4

A number that tells us whether of not we can reject the null hypothesis and accept the alternative hypothesis

Question 5

What are the 3 criteria for knowing which critical value to use?

Answer 5

• One or two-tailed test
• The number of participants in the study (‘N’ or ‘df’)
• The level of significance (0.05 if another not stated)

Question 6

What is the rule of r?

Answer 6

If the test has an R in it then the calculated value should be more than the critical value (chi-squared, spearmans, u-t-test, r-t-test, pearsons)
If the test doesn’t have an R in it then the calculated value should be less than the critical value

Question 7

What is a type 1 error?

Answer 7

TOO LENIENT, ‘optomistic’ ‘false positive’ - when the null hypothesis is rejected and the alternative hypothesis is accepted when it should have been the other way round because, in reality, the null hypothesis is ‘true’

Question 8

What is a type 2 error?

Answer 8

‘Pessamistic’ ‘false negative’ - When the null hypothesis is accepted but it should have been the alternative hypothesis
–Can happen when putting the significance level at 0.01% and it should have been 0.05%