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.

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
testdisease presentdisease absenttotalpositive255216471abnegative515841589cdtotal26018002060

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 = 255b = 216c = 5d = 1584
NPV = %
2.Easy
testdisease presentdisease absenttotalpositive141240381abnegative49720769cdtotal1909601150

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 = 141b = 240c = 49d = 720
PPV = %
3.Medium
casescontrolsexposed157159abnot exposed223451cd

Practice exercise (made-up values, not clinical guidance). A case-control study compares 380 patients with a disease (cases) and 610 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 = 157b = 159c = 223d = 451
OR =
4.Medium
peopleyears14101.525805new cases112

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

410 × 1.5 years580 × 5 years112 new cases
IR = per 1000 person-years
5.Hard
p (%)PPV (%)10%PPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 71% and a specificity of 90%. 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 = 71%Sp = 90%p = 10%
PPV = %
6.Hard
p (%)PPV (%)30%PPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 76% and a specificity of 84%. It is used in a population where the prevalence is 30%. Find the positive predictive value PPV as a percentage. Round to one decimal place.

Se = 76%Sp = 84%p = 30%
PPV = %

Answer key

  1. 1. NPV = 99.7 %
  2. 2. PPV = 37 %
  3. 3. OR = 2
  4. 4. IR = 31.9 per 1000 person-years
  5. 5. PPV = 44.1 %
  6. 6. PPV = 67.1 %

Full step-by-step solutions: practise this topic on examproblems.com.