Chapter 13

Question 1

‘Failing to reject’ null hypothesis usually because…

Answer 1

• no relationship between variables
• IV manipulation was weak
• DV measure was not sensitive enough
• we chose a very stringent (precise) significance level
• sample sive was too small
• effect size was too small
• use got unlucky

Question 2

Interpreting Significant Results

Answer 2

• statistically significant is does not equal it being important, it only means there is a very low probability that results occurred by chance alone

Question 3

Null hypothesis

Answer 3

that the population means are equal and any difference we found is due to random chance

Question 4

Research hypothesis

Answer 4

the means are not equal, then we would reject the null
- determine stastical significance: that tere is a very low probability that the difference we see between our sample means is due to random error

Question 5

type 1 error

Answer 5

A type I error occurs when in research when we reject the null hypothesis and erroneously state that the study found significant differences when there indeed was no difference.

Question 6

type II

Answer 6

A type II error, or a false negative, is the failure to reject a null hypothesis that is actually false.

Question 7

equation for (effect size)

Answer 7

(group difference)/(within-group variability)

Question 8

Group difference formula

Answer 8

Mean of Group 1 - Mean of Group 2