Winter 2023 Recall the following situation from HW3. A retail bank believes the replacement cycle for lost ATM cards is normally distributed with a mean of 10 days and a standard deviation of 3.75 days. In an attempt to reduce customer dissatisfaction with the time delays in replacing lost ATM cards, a retail bank monitors replacement cycle time for 5 requests each week for a period of 20 weeks. The data is shown in the table at the end of this assignment. The table also gives the mean, standard deviation, and the range of the replacement time in each subgroup. The data has been saved in a file named hw3_data.csv on Canvas. Consider Time2. Assuming that the true mean and the true standard deviation are unknown, complete the following.
(a) (10 pts) Create an Individuals (I) Chart. Calculate each of the following and draw the chart: - Centerline - 1-sigma limits - 2-sigma limits - 3-sigma limits
(b) (2 pts) Based on the Individuals chart in part (a), does the process appear to be in control with respect to the mean? Use the Western Electric Handbook rules to justify your answers.
(c) (6 pts) Create a Moving Range (MR) Chart. Find the following and draw the chart: - Centerline - 3-sigma limits
(d) (2 pts) Based on the MR chart in part (c), does the process appear to be in control with respect to the variation? Use the Western Electric Handbook rules to justify your answers.