Stats

Question 1

Confidence interval and statistical significance concept

Answer 1

• Cannot cross the null value (or is considered statistically non significant)

Question 2

How sensitivity and specificity relate to positive and negative predictive value

Answer 2

• sensitivity is the probability that a patient with a given disease will test positive for the disease. Thus, tests with high sensitivity can better rule out a disease (negative predictive value)
• specificity is the probability that a patient without a given disease will test negative for the disease. Tests with high specificity can better rule in a disease (positive predictive value)
  Spin, Snout

Question 3

Type of study Odds ratios are typically used in + concept

Answer 3

• case control studies
• odds that an outcome will occur given a particular exposure as compared to the odds of the outcome occurring in the absence of that exposure

Question 4

Crude odds ratio vs. fully adjusted odds ratio

Answer 4

crude = unadjusted (no confounders adjusted for)

Question 5

Positive likelihood ratio calculation

Answer 5

sensitivity over (1 - specificity)

Question 6

Negative likelihood ratio calculation

Answer 6

= (1 - sensitivity) over specificity

*reciprocal of positive likelihood ratio

Question 7

Benefit of LR’s

Answer 7

Since they are calculated from sensitivity and specificity, they don’t change with the prevalence of the disease