probability and significance

Question 1

what is probability

Answer 1

• a measure of the likelihood that a particular event will occur
• 0 indicates statistical impossibility
• 1 indicates statistical certainty

Question 2

what is significance

Answer 2

• how sure we are that a difference or correlation exists
• significant result means the null hypothesis can be rejected

Question 3

what is the null hypothesis

Answer 3

• no difference between the conditions
• statistical test determines whether the hypothesis is true
• if we accept or reject the null hypothesis

Question 4

what is the level of significance

Answer 4

• the point at which a researcher can claim to have discovered a large enough difference or correlation within the data and claim an effect has been found
• usual level is 0.05 (5%)

Question 5

what are critical values

Answer 5

• numerical boundary or cut-off point between acceptance or rejection of a null hypothesis

Question 6

what is the criteria to establish what critical value to use

Answer 6

• one or two tailed test used
• numbers of participants in the study
• level of significance

Question 7

what is a type I error

Answer 7

incorrect rejection of a true null hypothesis

Question 7

what is a type II error

Answer 7

failure to reject a false null hypothesis