To Dr. Sarim or who can help to answer this Q.... - my250

[ArchivalUser]

please help to answer to this q

In a case control study with using a two-tail ,how many patients would be needed to reduce the event rate from 8% to 4%?

Total number of patients =290
Exposed group=155
Event rate=16
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Unexposed group=135
Event rate=7


Thank you