Statistics

Question 1

what are P values?

Answer 1

numbers between 0-1 that quantify how confident we should be that drug A is different from drug B

Question 2

which P-value shows the most confidence?

Answer 2

P values closer to 0

Question 3

what is the accepted P-value?

Answer 3

0.05% (95%)

Question 4

a small p-value when there there is no difference is called…?

Answer 4

a false positive

Question 5

what are examples of dichotomous variables? (2)

Answer 5

• employed vs unemployed
• has disease vs does not have disease

Question 6

what is a reference population?

Answer 6

extracting a sample of a larger population

Question 7

what is the null hypothesis?

Answer 7

a statement that there is no relationship between the two variables that are tested

Question 8

what is the confidence interval?

Answer 8

range of values in which the actual value lies

Question 9

what is a type 1 error?

Answer 9

rejecting the null hypothesis when it is true

Question 10

what is a type 2 error?

Answer 10

accepting the null when it is false

Question 11

what does the box size represent on a forest plot?

Answer 11

the weight of the study

Question 12

what does the vertical line represent on a forest plot? (2)

Answer 12

• the line of no effect
• intervention has had no effect on outcome

Question 13

what does the horizontal line represent on a forest plot?

Answer 13

confidence interval

Question 14

what does the diamond represent on a forest plot?

Answer 14

the total meta-analytic result

Question 15

what does the peak of the diamond represent on a forest plot?

Answer 15

optimal result

Question 16

what does the sides of the diamond represent on a forest plot?

Answer 16

confidence intervals

Question 17

what is heterogenity?

Answer 17

differences between studies not due to chance

Question 18

what are the types of heterogenity? (2)

Answer 18

1. clinical
2. statistical

Question 19

what test is used for heterogenity?

Answer 19

chia-squared test

Question 20

what is a study population?

Answer 20

small sample of the entire population

Question 21

what is the confidence interval?

Answer 21

intervals computed from the sample data, which were the study repeated multiple times, would contain the true effect 95% of the time

Question 22

what is relative risk?

Answer 22

comparing the probability of the event occurring to all possible events considered in the study

Question 23

how is relative risk calculated?

Answer 23

incidence in exposed / incidence in non exposed

Question 24

what does it mean if the relative risk = 1?

Answer 24

incidence in exposed group is the same in non exposed

Question 25

what does it mean if the relative risk > 1?

Answer 25

incidence in exposed group is greater than in non exposed

Question 26

what does it mean if the relative risk < 1?

Answer 26

incidence in exposed group is lower than in non exposed

Question 27

“the further the relative risk is from 1…

Answer 27

…the stronger the association”

Question 28

which study can you not use relative risk in?

Answer 28

case control

Question 29

what is the odds ratio?

Answer 29

a measure of how strongly an event is associated with exposure

Question 30

how do you calculate odds ratio?

Answer 30

odds the case was exposed / odds the control was exposed

Question 31

what does it mean if the odds ratio = 1?

Answer 31

exposure is not associated with disease

Question 32

what does it mean if the odds ratio > 1?

Answer 32

exposure is positively associated with disease

Question 33

what does it mean if the odds ratio < 1?

Answer 33

exposure is negatively associated with the disease

Question 34

“the further the odds ratio is from 1…

Answer 34

…the stronger the association”

Question 35

which studies can you use odds ratios in? (2)

Answer 35

• cohort
• case controls