Statistics

Question 1

Negative predictive value

Answer 1

NPV=TN/TN+FN

Question 2

Sensitivity

Answer 2

TP=TP/TP+FN

Probability of a diseased person testing positive

Question 3

Specificity

Answer 3

TN/TN+FP

Probability of a non diseased person testing negative

Question 4

Positive predictive value

Answer 4

PPV=TP/TP+FP

Probability that an individual truly has a disease given a positive test result

Question 5

Number needed to harm

Answer 5

Indicates how many patients need to be exposed before a harmful event occurs in 1 patient
It is the inverse of absolute risk increase

Question 6

Absolute risk increase(ARI)

Answer 6

Difference in incidence rate between the exposed and nonexposed groups

Question 7

Number needed to treat

Answer 7

Determines the number of patients who need to be exposed to prevent 1 bad outcome
NNT is the inverse of absolute risk reduction

Question 8

Odds ratio

Answer 8

Measure of association between an exposure and an outcome
In other words, it represents the odds that an outcome(cardiovascular event) will occur in the presence of a particular exposure compared to the odds of that outcome in a control group
-OR>1 means the exposure is associated with higher odds of the outcome
-OR

Question 9

Positive likelihood ratio

Answer 9

Sensitivity/1-specificity

Represents the likelihood of having the disease given a positive result

Question 10

Negative liklihood ratio

Answer 10

1-sensitivity/specificity

Represents the liklihood of having the disease given a negative result