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 absenttotalpositive279160439abnegative31240271cdtotal310400710

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 = 279b = 160c = 31d = 240
PPV = %
2.Easy
testdisease presentdisease absenttotalpositive3372105abnegative717381745cdtotal4018101850

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 specificity Sp as a percentage. Round to one decimal place.

a = 33b = 72c = 7d = 1738
Sp = %
3.Medium
casescontrolsexposed9674abnot exposed14456cd

Practice exercise (made-up values, not clinical guidance). A case-control study compares 240 patients with a disease (cases) and 130 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 = 96b = 74c = 144d = 56
OR =
4.Medium
casescontrolsexposed26218abnot exposed164562cd

Practice exercise (made-up values, not clinical guidance). A case-control study compares 190 patients with a disease (cases) and 780 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 = 26b = 218c = 164d = 562
OR =
5.Hard
pre-test15%post-test?p′LR−

Practice exercise (made-up values, not clinical guidance). A patient has a pre-test probability of 15% for a disease. A test with sensitivity 62% and specificity 87% comes back negative. Find the post-test probability p′ of the disease as a percentage. Round to one decimal place.

pre-test 15%Se = 62%Sp = 87%negative
p′ = %
6.Hard
pre-test5%post-test?p′LR+

Practice exercise (made-up values, not clinical guidance). A patient has a pre-test probability of 5% for a disease. A test with sensitivity 61% and specificity 87% comes back positive. Find the post-test probability p′ of the disease as a percentage. Round to one decimal place.

pre-test 5%Se = 61%Sp = 87%positive
p′ = %

Answer key

  1. 1. PPV = 63.6 %
  2. 2. Sp = 96 %
  3. 3. OR = 0.5
  4. 4. OR = 0.41
  5. 5. p′ = 7.2 %
  6. 6. p′ = 19.8 %

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