Chapter 19 -- Exercise 32 |
Christina Sanders is a member of the women's basketball team at Windy City College. Last season, |
she made 55 percent of her free throw attempts. In an effort to improve this statistic, she attended a |
summer camp devoted to foulshooting techniques. |
The next 20 days she shot 100 foul shots a day. |
She carefully recorded the number of attempts made each day. The results are reported below |
|
To interpret, the first day she made 55 out of 100, or 55 percent. The last day she made 67 out of 100 |
or 67 percent. |
|
a. Develop a control chart for the proportion of shots made. Over the 20 days of practice, what |
percent of attempts did she make? What are the upper and lower control limits for the |
proportion of shots made? |
|
b. Is there any trend in her proportion made? Does she seem to be improving, staying the same, |
or getting worse? |
|
c. Find the percent of attempts made for the last five days of practice. Use the hypothesis testing |
procedure, formula (10–4), to determine if there is an improvement from 55 percent. |
|
|
|
Count |
Shots Made out of 100 |
1 |
55 |
2 |
61 |
3 |
52 |
4 |
59 |
5 |
67 |
6 |
57 |
7 |
61 |
8 |
59 |
9 |
69 |
10 |
58 |
11 |
57 |
12 |
66 |
13 |
63 |
14 |
63 |
15 |
63 |
16 |
65 |
17 |
63 |
18 |
68 |
19 |
64 |
20 |
67 |
Prob19-28 Chapter 19, Exercise 28 Steele Breakfast Foods, Inc., produces a popular brand or raisin bran cereal. The package indicates it contains 25.0 ounces of cereal. To ensure the product quality, the Steele inspection department makes hourly checks on the production process. As a part of the hourly check, 4 boxes are selected and their contents weighed. The results are reported below. 1) Develop an appropriate control charts . Label the UCL and LCL with a Bolded line so you can see where the point goes out of control. 2) What are the limits? Is the process out of control at any time? 3) Is the process out of control at any time? process: Find the Grand Mean, Find the average of the Ranges, Create a Control chart for the Mean and a control chart for the Range. Label the UCL and LCL with a Bolded line so you can see where the point goes out of control. SampleC1C2C3C4MeanRange 126.124.425.625.2 225.225.925.124.8 325.624.525.725.1 425.526.825.125.0 525.225.226.325.7 626.624.125.524.0 727.626.024.925.3 824.523.123.924.7 924.125.023.524.9 1025.825.724.327.3 1122.523.023.724.0 1224.524.823.224.2 1324.424.525.925.5 1423.123.324.424.7 1524.625.124.025.3 1624.424.422.823.4 1725.124.123.926.2 1824.524.526.026.2 1925.327.524.325.5 2024.625.325.524.3 2124.924.425.424.8 2225.724.626.826.9 2324.824.325.027.2 2425.425.926.624.8 2526.223.523.725.0 #30 Chapter 19, exercise 30 Lahey Motors specializes in sellng cars to buyers with a poor credit history. Listed below is the numer of cars that were repossessed from Lahey customers because they did not meet the payment obligations over each of the last 36 months. Develop a c-bar chart for the number repossessed. Were there any months when the number was out of control? Write a brief report summarizing your findings. You can write your report in this excel document. Repossed 6 5 8 20 11 10 9 3 9 9 15 12 4 11 9 9 6 18 6 8 9 7 13 7 11 8 11 13 6 14 13 5 5 8 10 11 #32 Chapter 19 -- Exercise 32 Christina Sanders is a member of the women's basketball team at Windy City College. Last season, she made 55 percent of her free throw attempts. In an effort to improve this statistic, she attended a summer camp devoted to foulshooting techniques. The next 20 days she shot 100 foul shots a day. She carefully recorded the number of attempts made each day. The results are reported below To interpret, the first day she made 55 out of 100, or 55 percent. The last day she made 67 out of 100 or 67 percent. a. Develop a control chart for the proportion of shots made. Over the 20 days of practice, what percent of attempts did she make? What are the upper and lower control limits for the proportion of shots made? b. Is there any trend in her proportion made? Does she seem to be improving, staying the same, or getting worse? c. Find the percent of attempts made for the last five days of practice. Use the hypothesis testing procedure, formula (10–4), to determine if there is an improvement from 55 percent. CountShots Made out of 100 155 261 352 459 567 657 761 859 969 1058 1157 1266 1363 1463 1563 1665 1763 1868 1964 2067 #33 Chapter 19 -- #38 38At the beginning of each football season, Team Sports, the local sporting goods store, purchases 5,000 footballs. A sample of 25 balls is selected, and they are inflated, tested, and then deflated. If more than two balls are found defective, the lot of 5,000 is returned to the manufacturer. Develop an OC curve for this sampling plan. a.What are the probabilities of accepting lots that are 10 percent, 20 percent, and 30 percent defective? b.Estimate the probability of accepting a lot that is 15 percent defective. c.John Brennen, owner of Team Sports, would like the probability of accepting a lot that is 5 percent defective to be more than 90 percent. Does this appear to be the case with this sampling plan?