We want to test the hypothesis that the mean number of credit hours taken per semester by OSU undergraduates is less than 16 hours.  Therefore, we obtain a random sample of credit hours for 49 students. The sample mean is 15 hours and the sample standard deviation is 4 hours.  We want to test:    Ho:  μ = 16 hours    Ha:  μ < 16 hours using a significance level (α) = 0.01. What is the calculated value of the test statistic needed to test the null hypothesis in this problem?

Frame score in beef cattle is based on height at the hips and is used as a measure of skeletal size.  Frame scores range from 1 to 10 with a higher number indicating a taller animal.  A randomized block design is used to compare the frame scores of Angus and Simmental calves where the blocks consist of calves of similar ages.  Three blocks are used, where block 1 contains calves that are 320 to 340 days of age, block 2 contains calves that are 341 to 360 days of age, and block 3 contains calves that are 361 to 380 days of age.  The frame scores are as follows:   Angus Simmental Block totals Block 1 5 6 11 Block 2 6 7 13 Block 3 7 8 15 Breed totals 18 21 39 The partially completed ANOVA table for this experiment is as follows: Source   df     SS     MS      F  Total   5.500     Breed   0.167 0.167 0.25 Block   4.000 2.000   Error   1.333 0.667   Calculate the F statistic for blocks.

What assumption is required for estimating the population mean (μ) when we have small samples of n < 30?

The ____________ in an experiment are the factor level combinations that are utilized.

The weaning weights of 3 herds of beef cattle are compared across the 4 seasons of the year.  Thus, this is a 3 x 4 factorial experiment with 3 herds and 4 seasons.  Three calves from each herd are sampled during each season (i.e., there are 3 replications).  The resulting data were analyzed using Analysis of Variance and the partially completed ANOVA table is as follows: Source              df            F            Total                  35 Herd                   2         17.2 Season               3          3.0 Herd x Season    6          1.2 Error                  24                              Was there a significant herd x season interaction?  Use a significance level of α = 0.05.

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?

Scientists are interested in determining if the mean alkalinity level of water specimens from the Han River in Seoul, Korea is greater than 50 milligrams per liter (mpl).  They select a random sample of 100 water specimens from the river and find a sample mean of 70 mpl and a sample standard deviation of 15 mpl.  They decide to test the hypothesis that the population mean for alkalinity level of water in the Han River exceeds 50 mpl using a significance level of 0.01.  Should the scientists reject or not reject the null hypothesis?  Explain.

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.

An animal scientist conducts a study to estimate the proportion of cows of the Charolais breed that require assistance during calving.  A random sample of 500 Charolais cows is selected.  Results of the study show that 100 of the 500 cows in the sample required assistance in giving birth.  What is the point estimate of the true population proportion (p) of Charolais cows that require assistance during calving?

The ____________ ____________ is the probability that a confidence interval encloses the true value of the population parameter, if the confidence interval procedure is used repeatedly a large number of times.