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 absenttotalpositive16954223abnegative51126177cdtotal220180400

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 = 169b = 54c = 51d = 126
PPV = %
2.Easy
testdisease presentdisease absenttotalpositive35162413abnegative39378417cdtotal390440830

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 accuracy Acc as a percentage. Round to one decimal place.

a = 351b = 62c = 39d = 378
Acc = %
3.Medium
testdisease presentdisease absenttotalpositive176178354abnegative24932956cdtotal20011101310

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 = 176b = 178c = 24d = 932
LR− =
4.Medium
casescontrolsexposed124101abnot exposed176289cd

Practice exercise (made-up values, not clinical guidance). A case-control study compares 300 patients with a disease (cases) and 390 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 = 124b = 101c = 176d = 289
OR =
5.Hard
p (%)PPV (%)10%PPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 90% and a specificity of 96%. 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 = 90%Sp = 96%p = 10%
PPV = %
6.Hard
pre-test20%post-test?p′LR+

Practice exercise (made-up values, not clinical guidance). A patient has a pre-test probability of 20% for a disease. A test with sensitivity 79% and specificity 68% comes back positive. Find the post-test probability p′ of the disease as a percentage. Round to one decimal place.

pre-test 20%Se = 79%Sp = 68%positive
p′ = %

Answer key

  1. 1. PPV = 75.8 %
  2. 2. Acc = 87.8 %
  3. 3. LR− = 0.14
  4. 4. OR = 2.02
  5. 5. PPV = 71.4 %
  6. 6. p′ = 38.2 %

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