I am trying to follow this guide to calculate the p-value from an incidence rate between two samples.

The raw data is patients' use of an action plan before and after education.

Before education 7 uses over 44.17 patient years were observed.
After education 41 uses over 101.5 patient years were observed.
Totals are then 48 uses over 145.67 patient years.

So I think following the guide the chi^2 value is: (41 - (48*101.5)/145.67 )^2 ((48*44.17*101.5) / 145.67^2) = 5.627.

How can I go from this chi^2 value to a p-value? Most calculators I can find online require a Degrees of Freedom parameter, but I'm not sure what that means in this context?


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.