probability and significance

Question 1

what does a null hypothesis state?

Answer 1

there is no difference between the conditions

Question 2

what does an alternative hypothesis state?

Answer 2

there is a difference between the conditions

Question 3

what is the usual level of significance in psych?

Answer 3

0.05 (5%)

Question 4

what is a type I error?

Answer 4

• incorrect rejection of a null hypotehsis which is actually true
• researchers claim to have found a significant difference when there actually isnt any (false positive)

Question 4

what is a type II error?

Answer 4

• failure to reject the null hypothesis that is false
• researchers calim there is no sigmificant difference when there actually is one ( false negative)