Thread: Probability Problem

This problem was in the textbook. To find the probability of mu we have P(-0.96<Z<1.09)=0.69. So I reasoned the probability of at least for was (0.69)^4(0.31)+(0.69)^5. But the solution has 5*(0.69)^4(0.31)+(0.69)^5. Maybe it is just last, but I'm not sure why we are multiplying by five.

Hey Hal2001.

Hint: For independent A and B, P(A and B) = P(A)P(B)

It was late . Woke up this morning and realized the five is simply the binomial coefficient......