Chicken Delight Claims That 92% Of Its Orders Are Delivered. 1.
value:
10.00 points
| Chicken Delight claims that 92% of its orders are delivered within 10 minutes of the time the order is placed. A sample of 80 orders revealed that 70 were delivered within the promised time. At the 0.01 significance level, can we conclude that less than 92% of the orders are delivered in less than 10 minutes? |
| a. | What is the decision rule? (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.) |
| Reject H0 if z < H0 : π ≥ 0.92 |
2.
value:
1.00 points
| The Damon family owns a large grape vineyard in western New York along Lake Erie. The grapevines must be sprayed at the beginning of the growing season to protect against various insects and diseases. Two new insecticides have just been marketed: Pernod 5 and Action. To test their effectiveness, three long rows were selected and sprayed with Pernod 5, and three others were sprayed with Action. When the grapes ripened, 400 of the vines treated with Pernod 5 were checked for infestation. Likewise, a sample of 400 vines sprayed with Action were checked. The results are: |
| Insecticide | Number of Vines Checked (sample size) |
Number of Infested Vines |
| Pernod 5 | 400 | 34 |
| Action | 400 | 38 |
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| At the .01 significance level, can we conclude that there is a difference in the proportion of vines infested using Pernod 5 as opposed to Action? Hint: For the calculations, assume the Pernod as the first sample. |
| 1. | State the decision rule. (Negative amounts should be indicated by a minus sign. Do not round the intermediate values. Round your answers to 2 decimal places.) |
| H0 is rejected if z < |
3.
value:
10.00 points
| The safety director of large steel mill took samples at random from company records of minor work-related accidents and classified them according to the time the accident took place. |
| Number of | Number of | |||||||
| Time | Accidents | Time | Accidents | |||||
| 8 up to 9 A.M. | 6 | 1 up to 2 P.M. | 5 | |||||
| 9 up to 10 A.M. | 7 | 2 up to 3 P.M. | 9 | |||||
| 10 up to 11 A.M. | 25 | 3 up to 4 P.M. | 24 | |||||
| 11 up to 12 P.M. | 7 | 4 up to 5 P.M. | 6 | |||||
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| Using the goodness-of-fit test and the 0.02 level of significance, determine whether the accidents are evenly distributed throughout the day. (Round your answers to 3 decimal places.) |
| H0: The accidents are evenly distributed throughout the day. H1: The accidents are not evenly distributed throughout the day. |
| Reject H0 if > H0. The accidents evenly distributed throughout the day. |
4.
value:
10.00 points
| The use of cellular phones in automobiles has increased dramatically in the last few years. Of concern to traffic experts, as well as manufacturers of cellular phones, is the effect on accident rates. Is someone who is using a cellular phone more likely to be involved in a traffic accident? What is your conclusion from the following sample information? Use the 0.05 significance level. (Round your answers to 3 decimal places.) |
| Had Accident | Did Not Have an Accident | |||
| in the Last Year | in the Last Year | |||
| Uses a cell phone | 20 | 300 | ||
| Does not use a cell phone | 40 | 450 | ||
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| H0: No relationship between phone use and accidents. |
| H1: There is a relationship between phone use and accidents. |
| Reject H0 if X2 > H0. There relationship between phone use and accidents. |
