Evidence-based practice statistics worksheet with answers

Free printable Evidence-based practice statistics worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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Name: ____________________   Date: ____________

1.Easy
testdisease presentdisease absenttotalpositive138306444abnegative9213041396cdtotal23016101840

Practice exercise (made-up values, not clinical guidance). A new test was compared with the reference standard in a study (see the 2 × 2 table). Find the sensitivity Se as a percentage. Round to one decimal place.

a = 138b = 306c = 92d = 1304
Se = %
2.Easy
testdisease presentdisease absenttotalpositive210138348abnegative70722792cdtotal2808601140

Practice exercise (made-up values, not clinical guidance). A new test was compared with the reference standard in a study (see the 2 × 2 table). Find the prevalence in the study p as a percentage. Round to one decimal place.

a = 210b = 138c = 70d = 722
p = %
3.Medium
Se79%Sp96%LR+ = ?

Practice exercise (made-up values, not clinical guidance). A test has a sensitivity of 79% and a specificity of 96%. Find the positive likelihood ratio LR+. Round to two decimal places.

Se = 79%Sp = 96%
LR+ =
4.Medium
peopleyears15601.52460531602new cases130

Practice exercise (made-up values, not clinical guidance). In a cohort, groups of people were followed for different lengths of time (see the table: number of people and years of follow-up for each). During follow-up, 130 new cases occurred. Find the incidence rate IR per 1000 person-years. Round to one decimal place.

560 × 1.5 years460 × 5 years160 × 2 years130 new cases
IR = per 1000 person-years
5.Hard
CER10%EER?RRR 34%

Practice exercise (made-up values, not clinical guidance). A treatment reduces the risk of an event by 34% in relative terms (RRR = 34%). In a patient group the risk without treatment (CER) is 10% over five years. Find the number needed to treat NNT for five years to prevent one event. Round up to a whole number of patients.

RRR = 34%CER = 10%
NNT =
6.Hard
p (%)PPV (%)20%PPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 96% and a specificity of 86%. It is used in a population where the prevalence is 20%. Find the positive predictive value PPV as a percentage. Round to one decimal place.

Se = 96%Sp = 86%p = 20%
PPV = %

Answer key

  1. 1. Se = 60 %
  2. 2. p = 24.6 %
  3. 3. LR+ = 19.75
  4. 4. IR = 37.6 per 1000 person-years
  5. 5. NNT = 30
  6. 6. PPV = 63.2 %

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