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 absenttotalpositive198366564abnegative122814936cdtotal32011801500

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 prevalence in the study p as a percentage. Round to one decimal place.

a = 198b = 366c = 122d = 814
p = %
2.Easy
testdisease presentdisease absenttotalpositive245300545abnegative115770885cdtotal36010701430

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 = 245b = 300c = 115d = 770
Sp = %
3.Medium
peopleyears145052801.531805new cases13

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

450 × 5 years80 × 1.5 years180 × 5 years13 new cases
IR = per 1000 person-years
4.Medium
eventno eventtotaltreatment28682710abcontrol33627660cd

Practice exercise (made-up values, not clinical guidance). In a randomised trial, 710 patients received a new treatment and 660 received the control treatment. The table shows how many in each group had the outcome (an unwanted event such as a stroke). Find the relative risk RR of the event with treatment. Round to two decimal places.

treatment: 28/710control: 33/660
RR =
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 92% and specificity 81%. The prevalence of the disease is 13%. How many positive results n₊ are expected in total?

N = 10 000p = 13%Se = 92%Sp = 81%
n₊ =
6.Hard
testdisease presentdisease absenttotalpositive?negativetotal10 000

Practice exercise (made-up values, not clinical guidance). 10 000 people are screened with a test of sensitivity 78% and specificity 93%. The prevalence of the disease is 12%. How many true-positive results TP are expected?

N = 10 000p = 12%Se = 78%Sp = 93%
TP =

Answer key

  1. 1. p = 21.3 %
  2. 2. Sp = 72 %
  3. 3. IR = 4 per 1000 person-years
  4. 4. RR = 0.79
  5. 5. n₊ = 2849
  6. 6. TP = 936

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