Step I biostat: interval years.

[stronghold]

A single year survival study was done on chemotherapy treatment in breast cancer, study results were:
Interval(years) # of patients # of survivors survival percentage
0-1 300 115 62
1-3 185 37 80
3-5 148 24 84
5-6 124 113 91

If a patient survived 5 years what is his percentile chance of surviving the 6th?

Is it 91 or 84 X 91?

 

[paul411]

Your last row of data is wrong: instead of # of deaths, you put the # of survivors.

If a patient has survived 5 years, he will fall into the last category (5-6). So the answer is 91.

If the subject had survived for 3 years and the question asked what the probability of surviving to 6 years was, then 84% * 91% (which is 76%) would be the answer.

 

[stronghold]

Thank you.