(17.20) Personal probability? When there are few data, we often fall back on per
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Question
(17.20) Personal probability? When there are few data, we often fall back on personal probability. There had been just 24 space shuttle launches, all successful, before the Challenger disaster in January 1986. The shuttle program management thought the chances of such a failure were only 1 in 100,000 (a) Suppose 1 in 100,000 is a correct estimate of the chance of such a fail- ure. If a shuttle was launched every day, about how many failures would one expect in 300 years? (b) Give some reasons such an esti mate is likely to be too optimistic.Explanation / Answer
(A)
The probability of failure is
P(failure) = 1/100000 = 0.00001
Number of days is 300 years (ignoring leap years) = 300 *365 = 109500
The expected number of failures in 300 years:
109500 * 0.00001 = 1.095
(b)
It said that in 109500 launches, only one launch failed (approximately). This number is very low so it seems to be too optimistic.
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