HCH's assembly unit has decided to use a p-Chart to monitor the proportion of defective castings produced by their production process. The control limits on these charts will be designed to include 98% of the sample proportions when the process is In Control. The operations manager randomly samples 250 castings at 12 successively selected time periods and counts the number of defective castings in the sample. Sample Defects
17
212
38
414
58
69
78
88
912
107

Required:
a. What is the Lower Control Limit?
b. What is the Upper Control Limit?
c. What is the z score?

An annual marathon covers a route that has a distance of approximately 26 miles. winning times for this marathon are all over 2 hours. the following data are the minutes over 2 hours for the winning male runners over two periods of 20 years each. earlier period 14 12 15 22 13 10 19 13 9 14 20 18 16 20 23 12 18 17 6 13 recent period 7 11 7 14 8 9 11 14 8 7 9 8 7 9 9 9 9 8 10 8 (a) make a stem-and-leaf display for the minutes over 2 hours of the winning times for the earlier period. use two lines per stem. (use the tens digit as the stem and the ones digit as the leaf. enter none in any unused answer blanks. for more details, view how to split a stem.) minutes beyond 2 hours earlier period 0 1 2 (b) make a stem-and-leaf display for the minutes over 2 hours of the winning times for the recent period. use two lines per stem. (use the tens digit as the stem and the ones digit as the leaf. enter none in any unused answer blanks.) minutes beyond 2 hours recent period (c) compare the two distributions. how many times under 15 minutes are in each distribution