Relative risk

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The ratio of the risk (or probability) of an event for one group to the risk of the same event for a second group.

Example

The following data were collected on a random sample of students enrolled in a Statistics course at the University of Auckland.



Attendance
    Regular Not regular Total
Course

result
Pass

Fail
83

17
19

27
102

44
  Total 100 46 146



The risk of failing for students with non-regular attendance = 27/46 = 0.5870

The risk of failing for students with regular attendance = 17/100 = 0.17

The relative risk of failing for students with non-regular attendance compared to those with regular attendance = 0.5870/0.17 = 3.5

This can be interpreted as the risk of failing for students with non-regular attendance is about 3.5 times the risk of failing for students with regular attendance.

Curriculum achievement objectives references

Probability: Levels 7, (8)