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In the 1970’s it was generally assumed that the mean birth weight of Angus beef cattle was 75 lb.  A researcher believes that, due to selection for increased size and growth rate in Angus, the average birth weight is now greater than 75 lb.  He obtains a random sample of n = 144 birth weights of Angus calves and calculates a sample mean of 85 lb and a sample standard deviation of 10 lb. Calculate the test statistic needed to test the null hypothesis.

The College of Food, Agricultural, and Environmental Sciences wants to estimate the proportion of students that are female.  In a small pilot study, they obtain a sample estimate of 0.60 for the proportion of students in the college that are female.  What sample size would be needed if the college administration wanted to estimate the proportion of students that are female correct to within 0.03 with a probability of 0.98?

Assuming that n1 = n2, find the sample sizes needed to estimate (p1 – p2) correct to within 0.07 with probability 0.90.  Assume that there is no prior information available to obtain sample estimates of p1 and p2.

The probability of making a Type I error in hypothesis testing is called the __________________ for a hypothesis test.

If we conduct a matched pairs experiment using small samples, what assumptions are needed for the small-sample confidence interval for the mean difference to be valid?

You are interested in purchasing a new car.  One of the many points you wish to consider is the resale value of the car after 5 years of ownership.  Since you are particulary interested in a certain foreign sedan, you decide to estimate the resale value of this car with a 90% confidence interval.  You manage to obtain data on 16 recently resold 5-year-old foreign sedans of that model.  These 16 cars were resold at an average price of $10,000 with a standard deviation of $1,500. You estimate the true population mean for the resale value of this model of foreign car using a 90% confidence interval.  What assumption must be met in order for the confidence interval that you constructed to be valid?

A Gallop poll is conducted to estimate the proportion of voters who plan to vote in favor of a certain issue 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.  Construct a 99% confidence interval for the true population proportion of people who plan to vote in favor of the issue.

The manager of a swine operation wants to compare the litter sizes of three pigs of pigs – Duroc, Yorkshire, and Large White.  The manager obtains a random sample of litter sizes of sows of the three breeds as shown in the table below.  Use Analysis of Variance to test at the 0.05 significance level if there is a difference in the average litter sizes of the three breeds of pigs. Litter size Large White Duroc Yorkshire 10 6 11 6 7 8 8 9 13 12 4 10 6 6 10 10 12 5 6 8 6 Total 42 67 64 Average 8.4 6.7 10.7 What are the degrees of freedom for total, breed, and error in the Analysis of Variance table?

A random sample of n = 200 observations is selected from a binomial population.  The sample estimate of the proportion of successes is 0.13.  Using a significance level of α = 0.10, we want to test: Ho:  p = 0.10 Ha:  p > 0.10 Assuming that we can use large-sample procedures, calculate the value of the test statistic needed to test these hypotheses.

A plant breeder develops a new wheat variety she hopes will yield more in the plains than the three most popular varieties under dry-land farming conditions.  She sets up a randomized block experiment with the three major types of soil in the region – sand, clay, and loam – as the blocks.  She selects a field with each soil type, divides it into four sections, and randomly selects one of the four wheat varieties for planting in each section.  The yields in bushels per acre in each section are shown in the following table. Variety Block A B C D Total Sand 20 21 21 18 80 Clay 25 24 21 20 90 Loam 30 28 22 20 100 Total 75 73 64 58 270 What are the degrees of freedom for total, treatments (i.e., varieties), blocks (i.e., soil types) and error for this randomized block experiment?