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 absenttotalpositive454590abnegative58590cdtotal50130180

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 = 45b = 45c = 5d = 85
Se = %
2.Easy
testdisease presentdisease absenttotalpositive77752829abnegative3311281161cdtotal11018801990

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 = 77b = 752c = 33d = 1128
Sp = %
3.Medium
peopleyears150224401new cases4

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

50 × 2 years440 × 1 year4 new cases
IR = per 1000 person-years
4.Medium
casesperson-yearsexposed611500not exposed953500

Practice exercise (made-up values, not clinical guidance). In a cohort study, exposed people contributed 1500 person-years with 61 new cases, and unexposed people 3500 person-years with 95 new cases. Find the incidence rate ratio IRR (exposed versus unexposed). Round to two decimal places.

exposed: 61/1500 PYnot exposed: 95/3500 PY
IRR =
5.Hard
testdisease presentdisease absenttotalpositive?negativetotal10 000

Practice exercise (made-up values, not clinical guidance). 10 000 people are screened with a test of sensitivity 70% and specificity 95%. The prevalence of the disease is 16%. How many positive results n₊ are expected in total?

N = 10 000p = 16%Se = 70%Sp = 95%
n₊ =
6.Hard
p (%)NPV (%)1%NPV = ?100

Practice exercise (made-up values, not clinical guidance). A screening test has a sensitivity of 95% and a specificity of 88%. It is used in a population where the prevalence is 1%. Find the negative predictive value NPV as a percentage. Round to one decimal place.

Se = 95%Sp = 88%p = 1%
NPV = %

Answer key

  1. 1. Se = 90 %
  2. 2. Sp = 60 %
  3. 3. IR = 7.4 per 1000 person-years
  4. 4. IRR = 1.5
  5. 5. n₊ = 1540
  6. 6. NPV = 99.9 %

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