stats/research

Question 1

sensitivity

Answer 1

few false negatives, good screening test.

TP/(TP+FN)

Question 2

specificity

Answer 2

few false positives.

TN/(TN+FP)

Question 3

PPV

Answer 3

prob that someone who tests positive has the disease

TP/(TP+FP)

Question 4

NPV

Answer 4

prob that someone who tests negative does not have the disease
TN/(TN+FN)

Question 5

type I error

Answer 5

reject null hypothesis in error - think something is significant when it really isn’t

Question 6

type II error

Answer 6

accept null hypothesis in error - think something isn’t significant when it really is

Question 7

validity

Answer 7

whether test measures what it’s intended to.
internal validity = accuracy
external validity = generalizability

Question 8

reliability

Answer 8

consistency of results from a test

Question 9

intention to treat

Answer 9

all patients must remain in the group to which they were randomly assigned - maintains power

Question 10

NNT

Answer 10

NNT = 1/absolute risk reduction
ARR = rate in untreated - rate in treated

Question 11

incidence

Answer 11

number of newly diagnosed cases

Question 12

prevalence

Answer 12

total number of cases existing at a given time

Question 13

likelihood ratio

Answer 13

likelihood that a person with condition will have a positive test.

Question 14

relative risk

Answer 14

probability of outcome in exposed group vs unexposed group

Question 15

odds ratio

Answer 15

odds of an outcome in exposed vs unexposed group

Question 16

cohort study

Answer 16

comparison of group with exposure to control w/o exposure

needs large sample size and long time, can lose people to follow up

Question 17

case control

Answer 17

start with patients with and without DISEASE and check for hx of risk factors

Question 18

cross sectional study

Answer 18

looking at associations at one point in time

Question 19

longitudinal studies

Answer 19

studying one gropu over time

Question 20

systematic review

Answer 20

summarizes articles on one topic

• specific clinical question
• thorough search for studies
• clear explanation for which studies were considered
• descriptive results section summarizing

Question 21

meta-analysis

Answer 21

• summary statistic using data from all studies
• report whether combining all statistics is possible
• assess for publication bias