Question

An accounts department is concerned about the number of internal purchase forms that its users completed incorrectly. As a result they are monitoring the proportion of purchase forms that were not completed correctly. This was chosen, rather than measuring the actual number of defects, because any number of defects on a form required about the same effort to revise. The following table shows number of forms completed incorrectly "out of 200 forms" that is processed each day. Construct a control chart for the data that monitors the proportion of incorrect forms. Is the process in control?

Day	Number of Incorrect Forms
1	18
2	19
3	18
4	18
5	25
6	18
7	20
8	20
9	18
10	20
Sum	194

IMPORTANT: In this problem, keep 3 decimal places in your calculations.

1. Which of the following charts is appropriate?
   1. P Chart
   2. C Chart
2. Based on your choice on the last question, calculate "one" of the followings: P (for P chart), or C (for C chart)
3. If you chose P Chart, how much is standard deviation of p (sigma_p)? (Leave empty if you are not doing P chart)
4. Upper Control Limit:
5. Lower Control Limit:
6. Is the proportion of incorrect forms in control?
   1. Yes
   2. No

Answer 1

P chart is drawn for the same and yes the incorrect forms are in control as we can see from the p chart that it is within the upper control limit and lower control limit.