Question

true negative - means the patient tests negative and is actually not infected as well
false negative - means the patient tests negative but is actually infected
statistics useful for a patient
positive predictive value (ppv) - the probability a patient is infected given they tested positive
negative predictive value (npv) - the probability a patient is not infected given they tested negative
statistics useful for scientists working on the screening test
sensitivity - the probability a patient tests positive given they are infected
specificity - the probability a patient tests negative given they are not infected
(the following two are the opposite probabilities of the previous two)
false negative rate - the probability a patient tests negative given they are infected
false positive rate - the probability a patient tests positive given they are not infected
2 fill in the blank 13 points
fill out the table above using the following clues based on scientific statics for this screening test.
450 patients were tested
50 of the patients had the disease
the false negative rate was 2%
the false positive rate was 10.25%
based on your answers in the table above, calculate the following statistics. (i recommend that you check your w
what is the sensitivity of the test? 98%

Explanation:

Step1: Identify known values

Total patients = 450, Infected patients = 50, False - Negative Rate = 0.02, False - Positive Rate = 0.1025

Step2: Calculate number of non - infected patients

Non - infected patients=450 - 50 = 400

Step3: Calculate false positives

False positives = 0.1025×400 = 41

Step4: Calculate true negatives

True negatives=400 - 41 = 359

Step5: Calculate false negatives

False negatives = 0.02×50 = 1

Step6: Calculate true positives

True positives=50 - 1 = 49

Step7: Calculate totals for rows and columns

Negative total = 359+1 = 360
Positive total = 41 + 49 = 90
Total for not infected column = 359+41 = 400
Total for infected column = 1+49 = 50
Total for all = 360+90 = 450

	Not infected	Infected	Total
Positive	41	49	90
Total	400	50	450

Answer:

	Not infected	Infected	Total
Positive	41	49	90
Total	400	50	450