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Review the three quick checks that should be used in evaluating a multiple-regression model.
Have The Gap sales generally followed a linear path over time? Does the graph suggest to you that some accommodation for seasonality.
The number of tons of brake assemblies received at an auto parts distribution center last month was 670. The forecast tonnage was 720.
The Gap sales as a function of disposable personal income as the basis for a forecast of The Gap sales for 2006.
What are the steps that should be used in evaluating regression models? Write each step in the order it should be evaluated.
Using The Gap data, which are not adjusted to remove the seasonality, what exponential smoothing model do you think would be the most appropriate.
Assume that the weights of college football players are normally distributed with a mean of 205 pounds and a standard deviation of 30.
Larry Bomser has been asked to evaluate sizes of tire inventories for retail outlets of a major tire manufacturer.
In 2006, The Gap sales by quarter were as given below-Based on these data, calculate a 95 percent confidence interval for quarterly sales of The Gap.
Use the first naive forecasting model presented in this chapter to prepare a forecast of retail store sales for each year from 2 through 8.
If this number is based on a random sample of 100 slices, and the population standard deviation is 30 calories, give a 90% confidence interval.
The manufacturer of batteries used in small electric appliances wants to estimate the average life of a battery.
The U.S. Center for Disease Control reports that the mean life expectancy for whites born in 1900 was 47.6 years and for nonwhites it was 33.0 years.
Which one is the preferable method and why? Indicate the pros and cons associated with probability and nonprobability sampling methods.
The user of the statistics claims your interval is too wide to have any meaning in the specific use for which it is intended.
A telephone company wants to estimate the average length of long-distance calls during weekends.
A transportation company wants to estimate the average length of time goods are in transit across the country.
A random sample of 40 executives gives x = $42,539 and s = $11,690. Give a 90% confidence interval for the average salary.
Discuss, in relative terms, the sample size needed for an application of a normal distribution for the sample mean when sampling.
An insurance company handling malpractice cases is interested in estimating the average amount of claims against physicians of a certain specialty.
For advertising purposes, the Beef Industry Council needs to estimate the average caloric content of 3-ounce top loin steak cuts.
A mining company needs to estimate the average amount of copper ore per ton mined. A random sample of 50 tons gives a sample mean of 146.75 pounds.
According to Money, the average price of a home in Albuquerque is $165,000.6 Suppose that the reported figure is a sample estimate.
A wine importer needs to report the average percentage of alcohol in bottles of French wine. From experience with previous kinds of wine.
British Petroleum has recently been investing in oil fields in the former Soviet Union. Before deciding whether to buy an oilfield.