I have 13 similar independent units and I need to calculate the probability at least 6 of them to survive for time less than 1.10.
From a table with the Kaplan-Meir estimates I get the following;
Time 1.05614 , 1.31581 number at risk 19 , 18 number failed 1,1 survival Prob. 0.474771 , 0.448395
I have omitted the previous and the next values because
Time=1.10 is between those two values and
P(T<1.10)=F(1.10)=F(1.05614)=1-survival prob.=1-0.474771= 0.525229
Which is the probability for 1 unit to survive for less than 1.10 hours? I don't know to continue from that point.