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The weights in pounds of 23 dogs were used to construct the following stem-and-leaf display using the first digit as the stem and the second digit as the leaf:. Stem     Leaves                                                    3            2     4 4            0     3     4     5     7     8     9 5            0     1     2     3     4     5 6            1     2     5     6     7 7            0     1 8 9            8 Use the stem-and-leaf display to find the upper quartile.

An animal scientist is interested in determining the proportion of ewes (i.e., female sheep) that give birth to twins.  Rather than examine the records for all ewes in the United States, the animal scientist randomly selects 500 ewes and finds that 220 of them gave birth to twins. Construct a 99% confidence interval to estimate the true population proportion of ewes, p, who give birth to twins.  Interpret the meaning of this confidence interval.

The mean grade on an Organic Chemistry exam is a 50 and the standard deviation of the grades is 10.  The highest grade in the class was a 95.  Calculate the z-score for the student with the highest score of 95.  Based in the z-score, is this grade of 95 an outlier?  Why or why not?

Suppose that 80% of the Holstein cows in the U.S. give birth to their calves with no calving difficulty.  We randomly select 7 Holstein cows from the population consisting of all Holstein cows in the U.S.  What is the probability that at least 5 of the 7 (i.e., 5 or more) cows in this sample will give birth to their calves with no calving difficulty?  To find the answer to this question, you can use the equation for the binomial distribution or a binomial probability table.

Find the sample size needed to estimate the population proportion (p) correct to within 0.06 with probability 0.95.  Assume that we have previous information that indicates that p = 0.30.

The average weight of a kennel of dogs is 40 lb and the standard deviation of the weights is 5 lb.  Find the probability that a randomly selected dog will weigh more than 48 lb.

A Gallop poll is conducted to estimate the proportion of voters who plan to vote in favor of a certain issuse on the ballet.  A random sample of 500 people of voting age is selected.  Results of the poll show that 300 of the 500 people polled plan to vote in favor of the issue.  Perform the calculations needed to determine whether or not it would be appropriate to construct a large-sample confidence interval for the true population proportion.  What do you conclude (i.e., is it appropriate?

A national organization has been working with electric companies throughout the US to find sites for large windmills to generate electric power.  Wind speeds must average more than 21 miles per hour (mph) for a site to be acceptable.  Recently, the organization conducted tests at a particular site where windmills are under construction.  Based on a sample of n = 40 wind speed recordings (taken at random intervals) at the site, the wind speeds averaged 23 mph with a standard deviation of 3.9 mph.  To determine whether the site meets the organization’s requirements, they want to test:    Ho:  μ = 21 mph    Ha:  μ > 21 mph using a significance level (α) = 0.01. Calculate the value of the test statistic needed to test the null hypothesis.

Independent random samples of litter sizes were selected from the Yorkshire and Landrace breeds of swine with the following results: Yorkshire          Landrace 8 pigs                    7 pigs 9                            8 10                          9 8                            8 9                            7 10                               54                        39  The correction factor (correction for the mean) in this problem is 786.27272. Calculate the Error Sums of Squares.

An Animal Scientist wants to estimate the average weaning weight of the Angus breed of beef cattle.  Therefore, he selects a random sample of 100 Angus calves and weighs them on the day they are weaned from their mothers.  The sample mean for these 100 calves is 500 lb and the sample standard deviation is 40 lb.  Which one of the following is the correct 90% confidence interval used to estimate the population mean for the weaning weights of the Angus calves?