Before revision: Inference Risk difference can be estimated from a 2x2 contingency table: Experimental group (E)Control group (C) TotalEvents (E) EE = 75CE = 100115Non-events (N) EN = 75CN = 150285Total150250400The point estimate of the risk difference is The sampling distribution of RD is approximately normal, with standard errorThe confidence interval for the RD is then where is the standard score for the chosen level of significance.
After revision: Inference Risk difference can be estimated from a 2x2 contingency table: GroupExperimental (E)Control group (C) Events (E) EECENon-events (N) ENCNThe point estimate of the risk difference is The sampling distribution of RD is approximately normal, with standard errorThe confidence interval for the RD is then where is the standard score for the chosen level of significance.