Exam One - Hypothesis testing

Question 1

hypothesis testing

Answer 1

inferential statistics provide a mechanism to reject that an observed effect is a chance occurrence

Question 2

alpha

Answer 2

describes the possibility of concluding two samples are different when they are not

Question 3

type 1 error

Answer 3

describes the possibility of concluding two samples are different when they are not

Question 4

alpha is type ___ error

Answer 4

one

Question 5

means for samples outside the 95% CI are ____

Answer 5

rare

Question 6

your tolerance for declaring a sample mean “significantly different” if it falls outside the expected range by chance is called the…

Answer 6

alpha level

Question 7

Beta level

Answer 7

probability of incorrectly concluding that two samples are NOT different

Question 8

probability of incorrectly concluding that two samples are NOT different

Answer 8

type 2 error

Question 9

beta level is type _____ error

Answer 9

two

Question 10

Power =

Answer 10

1 - beta

Question 11

power is the probability of…

Answer 11

correctly concluding that the groups are different

Question 12

typical power level acceptable for clinical research is

Answer 12

80%

Question 13

What are the factors affecting power?

Answer 13

• alpha level
• difference between group means
• within group variability
• sample size

Question 14

How does alpha level affect power?

Answer 14

• raising a increases power (also increases risk of type one error)
• one tailed tests also increase power

Question 15

How does the difference between group means affect power?

Answer 15

• larger group differences increases power

Question 16

how does within group variability affect power?

Answer 16

• decreased variability increases power
• increased variability decreases power

Question 17

How does sample size affect power?

Answer 17

• more subjects = more power
• narrow sampling distributions
• difference between means of large samples is more likely to be recognized as atypical

Question 18

prior to data collection, researchers perform a sample size estimate to demonstrate the study has sufficient _______

Answer 18

power (the ability to identify a true difference)

Question 19

What factors affect calculating sample size?

Answer 19

• alpha level
• difference between group means
• within group variability
• desired power (1-beta)

Question 20

When do we calculate the effect size?

Answer 20

used for sample size estimation
- estimates the magnitude of a treatment effect or difference between groups

Question 21

ES =

Answer 21

|diff b/t means|/ avg SD

Question 22

how to interpret ES

Answer 22

<0.4 = small
0.4-0.8 = medium
>0.8 = large

Question 23

increasing mean differences _______ effect size

Answer 23

increases

Question 24

increasing sample variability _____ effect size

Answer 24

decreases

Question 25

increasing sample size _____ effect size

Answer 25

no effect

Question 26

increasing effect size _____ sample size estimates

Answer 26

decreases

Question 27

increasing effect size _______ study power

Answer 27

increases

Question 28

increase type one error tolerance ______ study power

Answer 28

increases

Question 29

increasing sample size will ________ study power

Answer 29

increase