1.6 Considering Sample Size

Question 1

When we talk about power, we are referring to the

Answer 1

probability of rejecting the null hypothesis

Question 2

Studies may be underpowered if they have

Answer 2

too few participants

Question 3

Studies may be overpowered if they have

Answer 3

too many participants

Question 4

Estimating the right sample size increases the probability of _______________ and ensures that the study is both

Answer 4

detecting an effect; ethical and cost-effective

Question 5

An a priori power analysis is conducted

Answer 5

before your study takes place

Question 6

An a priori power analysis allows us to estimate the

Answer 6

sample size that we require to detect an effect based on our desired α level, the desired power level (1 - β), and the size of the effect

Question 7

An a priori power analysis allows us to control for both

Answer 7

Type 1 error probability, Type 2 error probability and control the power of the test

Question 8

A post-hoc power analysis is typically conducted

Answer 8

after your study takes place

Question 9

In a post-hoc power analysis, we already know the

Answer 9

outcome of our analysis

Question 10

A post-hoc power analysis allows us to use

Answer 10

the already known sample size (N), the set α level, and the specified effect size to return the power (1 - β) associated with the test

Question 11

Unfortunately, during a post-hoc analysis, you only control for the

Answer 11

a and not the b

Question 12

In psychology, we would generally set the desired alpha level at ________, and our beta level at _________.

Answer 12

05, i.e. α = 0.05; 0.20, i.e. β = 0.20

Question 13

Ultimately, if we set our beta level at________ , the power we would get for our sample would be _______

Answer 13

0.20; 0.8

Question 14

A power that is lower than 0.8, is typically considered to be:

Answer 14

too low for most areas of research