Stats

Question 1

Relative risk

Answer 1

Experimental event rate/ control event rate

Question 2

Normal distribution

Answer 2

Mean = median = mode

Question 3

Standard error of the mean

Answer 3

Measure of spread, gets smaller as sample size increases

SD/ sq root (n)

Question 4

Absolute risk reduction

Answer 4

Control event rate - experimental event rate

Question 5

Incidence

Answer 5

Number of new cases per population in given time period

Question 6

Prevalence

Answer 6

Total number of cases per population at a particular point in time

Question 7

Sensitivity

Answer 7

Ie picks up all cases

Negative result can rule out disease

Question 8

Power

Answer 8

Increased by sample size

= 1 - probability of type 2 error

Question 9

Type 1 error

Answer 9

Null hypothesis rejected when true

Question 10

Type 2 error

Answer 10

Null hypothesis accepted when it’s false

Question 11

Specificity

Answer 11

Ie recognises all healthy people as healthy

Number of true -ve / (true -ve + false positives)

Question 12

Cohort study

Answer 12

Selected according to exposure to particular agent and followed up to see how many develop outcome

Question 13

Case control

Answer 13

Rare conditions

Patients with certain condition identified and matched with controls

Question 14

Cross sectional study

Answer 14

Snapshot
Weak evidence of cause and effect
Observational study