# Question

The length of human pregnancies is approximately normally distributed with mean µ = 266 days and standard deviation σ = 16 days.

(a) What is the probability a randomly selected pregnancy lasts less than 260 days?

(b) Suppose a random sample of 20 pregnancies is obtained. Describe the sampling distribution of the sample mean length of human pregnancies.

(c) What is the probability that a random sample of 20 pregnancies has a mean gestation period of 260 days or less?

(d) What is the probability that a random sample of 50 pregnancies has a mean gestation period of 260 days or less?

(e) What might you conclude if a random sample of 50 pregnancies resulted in a mean gestation period of 260 days or less?

(f ) What is the probability a random sample of size 15 will have a mean gestation period within 10 days of the mean?

(a) What is the probability a randomly selected pregnancy lasts less than 260 days?

(b) Suppose a random sample of 20 pregnancies is obtained. Describe the sampling distribution of the sample mean length of human pregnancies.

(c) What is the probability that a random sample of 20 pregnancies has a mean gestation period of 260 days or less?

(d) What is the probability that a random sample of 50 pregnancies has a mean gestation period of 260 days or less?

(e) What might you conclude if a random sample of 50 pregnancies resulted in a mean gestation period of 260 days or less?

(f ) What is the probability a random sample of size 15 will have a mean gestation period within 10 days of the mean?

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