SOLUTION: 8.1 #6 Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean μ=176 and σ=9 days. I know the probability that

Algebra ->  Probability-and-statistics -> SOLUTION: 8.1 #6 Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean μ=176 and σ=9 days. I know the probability that       Log On


   

Question 1077770: 8.1 #6
Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean μ=176 and σ=9 days.

I know the probability that a randomly selected pregnancy lasts less that 173 days is about 0.3694.
However, my question is, what is the probability that a sample of 24 pregnancies has a mean gestation period of less than 173 days?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The std error of 24 pregnancy sample is sd of 9/sqrt (24)=1.837
z=(x-mean)/1.837, and here the z value is -1.633.
The probability that the mean of that sample will be < 173 days is 0.0512.