SOLUTION: 5)Suppose the length of pregnancy for hamsters is normally distributed with a mean of 40 days and a standard deviation of 2 days. We can say that 90% of pregnant hamsters wil

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Question 430607: 5)Suppose the length of pregnancy for hamsters is normally distributed with a mean of 40 days and a standard deviation of 2 days. We can say that 90% of pregnant hamsters will give birth before X days . Find X (Round off to nearest whole number of days.)
What is the conditional probability that the pregnancy will be shorter than 42 days given that it has lasted 38 days?
Answer by stanbon(75887) About Me  (Show Source):
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Suppose the length of pregnancy for hamsters is normally distributed with a mean of 40 days and a standard deviation of 2 days. We can say that 90% of pregnant hamsters will give birth before X days . Find X (Round off to nearest whole number of days.)
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Find the z-value with a 90% left-tail.
invNorm(0.90) = 1.2816
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Find "x" using x = zs+u
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X = 1.2816*2+40
X = 42.56 days
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Cheers,
Stan H.