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 absenttotalpositive19914213abnegative81226307cdtotal280240520

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 negative predictive value NPV as a percentage. Round to one decimal place.

a = 199b = 14c = 81d = 226
NPV = %
2.Easy
testdisease presentdisease absenttotalpositive277228505abnegative113342455cdtotal390570960

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 = 277b = 228c = 113d = 342
Sp = %
3.Medium
casescontrolsexposed2261abnot exposed8899cd

Practice exercise (made-up values, not clinical guidance). A case-control study compares 110 patients with a disease (cases) and 160 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 = 22b = 61c = 88d = 99
OR =
4.Medium
testdisease presentdisease absenttotalpositive211420631abnegative109630739cdtotal32010501370

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 negative likelihood ratio LR−. Round to two decimal places.

a = 211b = 420c = 109d = 630
LR− =
5.Hard
p (%)PPV (%)10%PPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 91% and a specificity of 88%. It is used in a population where the prevalence is 10%. Find the positive predictive value PPV as a percentage. Round to one decimal place.

Se = 91%Sp = 88%p = 10%
PPV = %
6.Hard
pre-test40%post-test?p′LR−

Practice exercise (made-up values, not clinical guidance). A patient has a pre-test probability of 40% for a disease. A test with sensitivity 79% and specificity 97% comes back negative. Find the post-test probability p′ of the disease as a percentage. Round to one decimal place.

pre-test 40%Se = 79%Sp = 97%negative
p′ = %

Answer key

  1. 1. NPV = 73.6 %
  2. 2. Sp = 60 %
  3. 3. OR = 0.41
  4. 4. LR− = 0.57
  5. 5. PPV = 45.7 %
  6. 6. p′ = 12.6 %

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