You update on the 7%, but the conditional probabilities of getting a positive result if you have and not have cancer respectively have also changed so that another positive test gives you less information than what it took to bring you from 1% to 7 %. See what ygert said.
You update on the 7%, but the conditional probabilities of getting a positive result if you have and not have cancer respectively have also changed so that another positive test gives you less information than what it took to bring you from 1% to 7 %. See what ygert said.