A+ Answers

Assignment #10  Chapter 9   

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1. You are the manager of a fast-food restaurant.  You want to determine whether the waiting time to place an order has changed in the past month from its previous population mean value of 4.5 minutes.  Develop the null and alternative hypothesis most appropriate for this situation.   (1 pt)

2. A stationary store owner knows the mean retail value of greeting cards last year was $2.50.  She believes that the mean value of the cards this year has increased.   Develop the null and alternative hypothesis most appropriate for this situation.   (1 pt)

3. Consider the following hypothesis test:
             
           
A sample of 57 items provided a sample mean of 28.1.  The population standard deviation is 8.46.  Use the critical value approach, at α = 0.05. Answer the following three questions.  (1 pt, 1 pt, 1 pt)

4. Consider the following hypothesis test:
             
           
A sample of 113 items provided a sample mean of 1215.  The population standard deviation is 100.  Use the p-value approach, at α = 0.05.  Answer the following three questions.    (1 pt, 1 pt, 1 pt)

5. A hole-punch machine is set to punch a hole 1.84 centimeters in diameter in a strip of sheet metal in a manufacturing process.  It is important to future steps in the process that the hole be punched to the specified diameter of 1.84 centimeters.  A sample of 12 strips of sheet metal produced a mean diameter of 1.85 centimeters and a sample standard deviation of 0.024 centimeters   At α = 0.05 does this sample show evidence that the true mean diameter differs from 1.84 centimeters?  Justify your answer using the t-distribution and the critical value approach.       (2 pts)