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 absenttotalpositive24380323abnegative77490567cdtotal320570890

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 positive predictive value PPV as a percentage. Round to one decimal place.

a = 243b = 80c = 77d = 490
PPV = %
2.Easy
testdisease presentdisease absenttotalpositive179544723abnegative1019261027cdtotal28014701750

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 = 179b = 544c = 101d = 926
Se = %
3.Medium
peopleyears120012480534301new cases12

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, 12 new cases occurred. Find the incidence rate IR per 1000 person-years. Round to one decimal place.

200 × 1 year480 × 5 years430 × 1 year12 new cases
IR = per 1000 person-years
4.Medium
casescontrolsexposed5651abnot exposed74169cd

Practice exercise (made-up values, not clinical guidance). A case-control study compares 130 patients with a disease (cases) and 220 people without it (controls). The table shows how many in each group were exposed to a risk factor. Find the odds ratio OR for the exposure. Round to two decimal places.

a = 56b = 51c = 74d = 169
OR =
5.Hard
pre-test10%post-test?p′LR−

Practice exercise (made-up values, not clinical guidance). A patient has a pre-test probability of 10% for a disease. A test with sensitivity 60% and specificity 93% comes back negative. Find the post-test probability p′ of the disease as a percentage. Round to one decimal place.

pre-test 10%Se = 60%Sp = 93%negative
p′ = %
6.Hard
p (%)PPV (%)1%PPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 73% and a specificity of 92%. It is used in a population where the prevalence is 1%. Find the positive predictive value PPV as a percentage. Round to one decimal place.

Se = 73%Sp = 92%p = 1%
PPV = %

Answer key

  1. 1. PPV = 75.2 %
  2. 2. Se = 63.9 %
  3. 3. IR = 4 per 1000 person-years
  4. 4. OR = 2.51
  5. 5. p′ = 4.6 %
  6. 6. PPV = 8.4 %

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