Biostatistics

Question 1

What is the gold standard of study designs?

Answer 1

Randomized control trials

Question 2

What is the evidence cycle?

Answer 2

Ask -> acquire -> appraise -> apply -> act

Question 3

PICO

Answer 3

Patient, Intervention, Comparison, Outcome

Question 4

Define: surrogate outcome

Answer 4

An outcome the patient can’t feel, but will affect how they feel ie. c-reactive protein as an indicator for inflammation

Question 5

List the strengths of a RCT.

Answer 5

1. Comparative

2. Decreased bias

Question 6

What are the types of bias?

Answer 6

1. Selection bias

2. Information bias

Question 7

Define: intent to treat

Answer 7

Data is analyzed as randomized.

Question 8

What are the types of data?

Answer 8

1. Continuous

2. Categorical

Question 9

Risk ratio

Answer 9

chance of risk in treatment group/chance of risk in control group

Question 10

RR > 1

Answer 10

Risk increase

Question 11

RR < 1

Answer 11

Risk reduction

Question 12

Define Type 1 error

Answer 12

The study finds a difference but there is no real difference

Question 13

Type 2 error

Answer 13

Study does not find a difference, but there is a real difference

Question 14

Alpha level

Answer 14

How tolerant you are of making a type 1 error. Usually set at 0.05

Question 15

Beta level

Answer 15

How tolerant you are of making a type 2 error

Question 16

Power

Answer 16

=(1-beta)*100

Question 17

What factors effect the Chi-squared test?

Answer 17

1. Sample size

2. Effect size

Question 18

RRI/R

Answer 18

1-RR = RRR
RR-1 = RRI

Question 19

ARR/I

Answer 19

ARR = subtraction of treated versus untreated [RR]

Question 20

NNT

Answer 20

=100/ARR (%)