Statistics

Question 1

Incidence?

Answer 1

New cases over period of time

Question 2

Prevalence

Answer 2

Total cases (new and old) at a particular point in time

Question 3

Sensitivity

Answer 3

-Ability to correctly DIAGNOSE disease
-Negative rules out (SnOUT)
-TP/TP+FN = Sn

Question 4

Specificity

Answer 4

-Ability to correctly EXCLUDE disease
-Positive rules in (SpIN)
-TN/TN+FP

Question 5

Positive Predictive Value

Answer 5

-Chances that a positive result is TRUE
-TP/TP+FP
-Increases with increased prevalence

Question 6

Negative Predictive Value

Answer 6

-Chances that a negative result is correct
-Increases with decreasing prevalence
-TN/(TN+FN)

Question 7

What is the p value?

Mean, median and mode?

Answer 7

Probability of chance of occurrence

Mean = average
Mode = value that appears most often
Median = middle set point

Skew right (positive) and left (negative)