Question 1152260
The point estimate of the reliability is 0.9
want to know if we raise 0.9 to some power, what is the probability at least 1 works.
This is 1- probability none of them works, and that must be 0.001
The probability one doesn't work is 0.1
The probability that none of x doesn't work is 0.1^x
when x=3, there are 3 smoke detectors that have a probability of 90% working and 10% not working.
The probability of all 3 not working is .001, so the probability of at least one working is 0.999.