Finding the value of test statistic for the given data and also interpret the result.
The Ratter Nursery Company packages their pine bark mulch in 50-pound bags. From a long history, the production department reports that the distribution of the bag weights follows the normal distribution and the standard deviation of this process is 3 pounds per bag. At the end of each day, Jeff Ratter, the production manager, weighs 10 bags and computes the mean weight of the sample. Below are the weights of 10 bags from today's production.
|
45.6
|
47.7
|
47.6
|
46.2
|
49.2
|
55.8
|
47.5
|
48.5
|
a. Can Mr. Ratter conclude that the mean weight of the bags is less than 50 pounds? Use the .01 significance level.
b. In a brief report, tell why Mr. Ratter can use the z distribution as the test statistic.