A dairy producer in Ohio wants to determine if the average milk production of her Holstein cows is greater than 18,000 lb of milk per lactation.  Therefore, she obtains a random sample of n = 100 milk production records from her herd and calculates a sample mean of 18,500 lb and a sample standard deviation of 3,500 lb. Should the dairy producer reject or not reject the null hypothesis using a significance level (α) = 0.05?  Explain.

A speed training program was effective in improving the 40-yard sprint times of high school athletes.  A study of 500 high school athletes was conducted to estimate p, the true proportion of all high school athletes who attained improved sprint times after participating in the speed training program.  The study showed that 425 of the 500 athletes had improved sprint times. Construct a 98% confidence interval to estimate the true population proportion of high school athletes who have improved sprint times as a result of participating in the speed training program.

Assuming that n1 = n2, find the sample sizes needed to estimate (μ1 – μ2) correct to within 2.5 with probability 0.90.  From prior experience we know that σ1 = 18 and σ2 = 16.

Suppose that 10% of the Labrador Retrievers in the U.S. have a particular genetic defect.  We randomly select 6 Labs from the population consisting of all Labs in the U.S.  What is the probability that exactly 2 of the 6 dogs in this sample have the genetic defect?

An animal scientist wants to determine the degree of association between carcass quality grade (variable X) and selling price per pound of carcass (variable Y).  The data for a random sample of 10 Angus steer carcasses are shown in the following table. Quality grade, X Carcass price per pound, Y 5 $1.09 7 1.19 4 0.99 5 1.04 8 1.21 6 1.18 4 0.94 7 1.15 8 1.23 6 1.12 Find the covariance between carcass quality grade and carcass price per pound.

The owner of Get-A-Way Travel has recently surveyed a random sample of 385 customers of the agency.  He would like to determine if the mean age of the agency’s customers is over 31 years.  If so, he plans to alter the destination of their special cruises and tours.  If not, no changes will be made.  He therefore wants to test:    Ho:  μ = 31 years    Ha:  μ > 31 years If he concludes that the mean age is not over 31 years when in fact it is over 31 years, he makes a ________ error.

The average height of a certain ornamental plant is 14 inches and the standard deviation of the heights is 2 inches.  Find the probability that a randomly selected plant will have a height between 12 and 18 inches.

The following table shows litter sizes for sows in four breeds of pigs. Yorkshire     Landrace     Hampshire     Duroc      8                   9                   8                 7     10                  9                   7                 8     11                10                   8                 9     11                10                   9                 7       9                  8                                                 49                46                 32               31 – treatment totals     9.8               9.2               8.0              7.5 – sample means     The experimental design shown here is a _______________.                                                                                  

Consider the probability distribution shown below for the random variable X:                                                                                                     X             10           20           30           40           50           60      P (X)     0.05        0.20        0.30         0.25        0.10         0.10      Find the mean of this discrete probability distribution.

A random sample of sale prices of homes in Columbus, Ohio yielded the following summary information:      Median = $125,000     Lower quartile = $82,000     Upper quartile = $168,000      Lowest price = $46,000     Highest price = $276,000 Construct a box plot for these data.  Based on this box plot, is the highest selling price of $276,000 a suspect or highly suspect outlier?