biostats

Question 1

What is the definition of sensitivity?

Answer 1

Probability of a disease person testing positive

Question 2

What is the formula for sensitivity?

Answer 2

TP/TP+FN

Question 3

What is the definition of specificity?

Answer 3

Probability of a non diseases person testing negative

Question 4

What is the formula for specificity?

Answer 4

TN/TN+FP

Question 5

What is the definition for positive predictive value?

Answer 5

Probability that the disease is present when you have a positive result

Question 6

What is the definition for negative predictive value?

Answer 6

Probability that the disease is absent when you have a negative result

Question 7

What is the definition for positive likelihood ratio?

Answer 7

Likelihood of having a disease with a positive test result

Question 8

What is the definition of negative likelihood ratio?

Answer 8

Likelihood of not having a disease with a negative test result

Question 9

What is the formula for positive likelihood ratio?

Answer 9

sensitivity/ 1- specificity

Question 10

What is the formula for negative likelihood ratio?

Answer 10

1-sensitivity/specificity

Question 11

What is primary prevention?

Answer 11

Educating and screening a patient to prevent disease. Action taken before patient develops disease

Question 12

What is secondary prevention?

Answer 12

Attempt to halting progression of disease

Question 13

What type of study should you calculate odds ratio?

Answer 13

case control studies

Question 14

What type of study should you calculate relative risk?

Answer 14

cohort study

Question 15

What is the definition of relative risk?

Answer 15

Risk of developing disease in exposed group/ risk of developing disease in the unexposed group

Question 16

What is the formula for relative risk?

Answer 16

(a/a+b)/(c/c+d)

Question 17

What is the formula for NNT?

Answer 17

1/ARR

Question 18

What is the formula of ARR?

Answer 18

(Events from controlled group) - (Events from treatment group)

Question 19

What is the formula for ARP?

Answer 19

Risk in exposed- risk in unexposed or RR-1/RR

Question 20

What is the formula for PARP?

Answer 20

Risk in total population - Risk in unexposed/ Risk in total population

Question 21

What is the formula for RRR?

Answer 21

1- RR

Question 22

What is the purpose of intention to treat analysis?

Answer 22

Protects randomization

Question 23

What is length time bias?

Answer 23

When you have a highly aggressive disease that is not able to be picked up by screening test. (Picks up benign cases)

Question 24

What is lead time bias?

Answer 24

When a screening test picks up a disease earlier than it would have been diagnosed leading to the assumption the patient has survived longer

Question 25

What is sensitivity analysis?

Answer 25

repeating primary analysis calculation after modifying certain criteria or variables

Question 26

What is propensity scoring and matching?

Answer 26

Ensuring balance between variables in treatment and control groups

Question 27

What is the standardized mortality ratio (SMR)?

Answer 27

Observed # of deaths/ expected # of deaths

Question 28

What is the net clinical benefit of a study?

Answer 28

The benefits and harms of a study

Question 29

What is verification bias?

Answer 29

When a study uses a gold standard test selectively

Question 30

What is the purpose of funnel plots?

Answer 30

helps in assessing publication bias

Question 31

What is analysis of variance?

Answer 31

Means of several groups are being compared

Question 32

What is the fisher exact test?

Answer 32

Study association between 2 variables with a small sample size

Question 33

What is accuracy?

Answer 33

Looks at how close you come to the gold standard

Question 34

What is precision?

Answer 34

looks at how often you get the same readings

Question 35

What is type 1 error?

Answer 35

when you say there is a association when there is really no association

Question 36

What is type 2 error?

Answer 36

When you say there is no association when an association actually exist

Question 37

Alpha is what type of error?

Answer 37

type 1 error

Question 38

Beta is what type of error?

Answer 38

type 2

Question 39

What is the formula for power?

Answer 39

1- beta

Question 40

What is the standardized incidence ratio?

Answer 40

determines if the occurrence of cancer in a small population is high or low relative to an expected value derived from a larger comparison population

Question 41

What is the formula for standardized incidence ratio?

Answer 41

observed cases/expected cases

Question 42

Which tests are most appropriate for screening?

Answer 42

Highly sensitive test

Question 43

Which tests are most appropriate for confirmatory test?

Answer 43

Highly specific tests

Question 44

What are factorial study designs?

Answer 44

utilizes 2 or more interventions and all combinations of the interventions

Question 45

What can threaten the internal validity of a study?

Answer 45

cofounding

Question 46

What is the case fatality rate?

Answer 46

refers to the proportion of patient with a particular disease who die from the disease