Question-1 The quality department of Lithion Corp uses control charts to monitor the life of the lithium-ion batteries produced by the company. The quality manager has returned from a course on statistical process control and has collected the data shown in the tab Battery Life. a. Using this data calculate 3-Sigma control limits for X-bar and R charts. b. Plot the sample means on the X-bar chart and the sample ranges on the R chart. c. Do the X-bar and R charts indicate that the process is in control? Why or why not? d. Because of rising demand a second shift has been added with some temporary workers. The control limits for the first shift are used for the second shift also. Six samples of battery life were taken from this shift. This data is shown in the tab Second Shift. Does this new indicate that battery life is still in control? Why or why not? Answer by plotting this new data against the control limits calculated in (a).

Question-2 MackAir is a rapidly growing airline promising people environmentally sensitive flights. One of MackAir's top competitive priorities is on-time arrivals. Each week for the past 30 weeks, Quality VP Jay Bondi has checked a random sample of 100 flight arrivals for on-time arrival and tracked the number of flights that did not meet MackAir's definition of "on time". This information is given in the tab Late Flights. a. Calculate the overall percentage of late flights and 99% (or 3-Sigma) upper and lower control limits of a p-chart for this situation. b. Assume that the airline industry's 99% upper and lower control limits for the percentage of flights that are not on time are 10% and 4%, respectively. How do these compare with the MackAir's control limits in (a)? c. Plot the percentage of late flights in each sample. Is the process that "produces" delayed flights at MackAir under control? d. What can VP Bondi report about the quality of service?

Question-3 A process filling small bottles with baby formula has a target of 3 ounces 0.10 ounces. In other words, a bottle must contain between 2.9 and 3.1 ounces of baby formula. As part of a periodic process capability study, two hundred bottles from the process were sampled. The results showed the average amount of formula filled in the bottles to be 2.972 ounces with a standard deviation of 0.023 ounces. a. Would you consider this process capable of meeting the required specifications? Answer by calculating an appropriate measure of capability. b. Assuming that the quantity of formula in a bottle is normally distributed, out of a batch of a million bottles how many do you think would be unacceptable - i.e., outside the specification limits? c. Currently the process is not centered. If the process is adjusted so that it becomes centered, what is the impact on the process capability measure that you calculated in (a)?

d. Assume that the process is centered. What should the process standard deviation be in order for the process to be considered Six-Sigma compliant (i.e., have Cp or Cpk of 2.0)?