Question

Question 1

Suppose that the distance of fly balls hit to the outfield (in baseball) is normally distributed with a mean of 248 feet and a standard deviation of 54 feet. We randomly sample 49 fly balls.

a) If X = average distance in feet for 49 fly balls, then give the distribution of X. Round your standard deviation to two decimal places.

X -N ( ?, ?)

b)What is the probability that the 49 balls traveled an average of less than 240 feet? (Round your answer to four decimal places.)

c) Find the 80th percentile of the distribution of the average of 49 fly balls. (Round your answer to two decimal places.)

Question 2

Among various ethnic groups, the standard deviation of heights is known to be approximately three inches. We wish to construct a 95% confidence interval for the mean height of males from a certain country. Forty-six males are surveyed from a particular country. The sample mean is 72 inches. The sample standard deviation is 2.2 inches.

a) Find the following. (Enter exact numbers as integers, fractions, or decimals.)

σ =

b) Construct a 95% confidence interval for the population mean height of males of this country.

State the confidence interval. (Round your answers to two decimal places.)

C)

d) Calculate the error bound. (Round your answer to two decimal places.)

Answer 1