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In: Statistics and Probability

1.) Suppose heights of two-year-olds are normally distributed with a mean of 30 inches and a...

1.) Suppose heights of two-year-olds are normally distributed with a mean of 30 inches and a standard deviation of 3.5 inches.

a) What is the probability that one two-year-old will be shorter than 28 inches?

b) If random samples of size n = 40 two-year-olds are selected, what is the approximate shape, mean, and standard deviation of the sampling distribution of sample means?

c) What is the probability that the sample mean of these 40 two-year-olds will be shorter than 28 inches? Why is the probability in part c) so much smaller than the probability in part a)?

d) What is the probability that the sample mean of these 40 two-year-olds will be taller than 31 inches?

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