The range of a population is approximately equal to __________.  (Hint:  remember the Empirical Rule)

A large labor union wishes to estimate the mean number of hours per month that union members are absent from work.  The union samples 475 of its members at random and monitors their working time for 1 month.  At the end of the month, the total number of hours absent from work is recorded for each employee.  The mean and standard deviation of the sample are 9.6 hours and 3.6 hours, respectively.  What is the point estimate of the mean (μ) of the entire population of number of hours absent from work per month?

Suppose x has a binomial probability distribution with n = 400 and p = 0.70.  Use the normal approximation to the binomial to find P (X 

The grades of 8 students on an exam were as follows: Student Grade 1 66 2 70 3 64 4 88 5 74 6 72 7 87 8 79     Find the variance of the grades of these 8 students.

Toyota would like to know how many miles per gallon the average driver gets when driving the hybrid Toyota Prius.  A random sample of 225 drivers yields a mean of 50 mpg and a standard deviation of 7.5 mpg. Estimate the population mean for the miles per gallon of the Prius using a 90% confidence interval.

The Kimberly Clark Corporation wants to determine how many tissues a box of Kleenex should contain.  Researchers determine that 60 is the average number of tissues used by a typical person during a cold.  Suppose a random sample of 100 Kleenex users yielded a sample mean of 56 tissues and a sample standard deviation of 10 tissues used during a typical cold.  Kimberly Clark wants to test:    Ho:  μ = 60 tissues    Ha:  μ < 60 tissues using a significance level (α) = 0.05. What is the correct critical value that should be used to test the null hypothesis?

Find the probability of an observation lying more than z = 1.77 standard deviations above the mean.

The birth weights (in pounds) of 17 calves are used to construct the following stem-and-leaf display: Stem                                 Leaf                                 3             4 4 5 6            5 7            4     5     7     9 8            2     4     5     6     8     9 9            2     3     5     6     8 What is the upper quartile for this data set?

Assume that 15% of all pigs die between birth and weaning.  In a random sample of 200 births, let X be the number of pigs that die between birth and weaning.  Using the normal approximation to the binomial, find the approximate probability that the number of pigs in the sample of 200 that die between birth and weaning is greater than or equal to 40.

The average height of a herd of cows is 50 inches and the standard deviation of the heights is 5 inches.  Find the probability that a randomly selected cow will have a height of more than 62 inches.