TE's Long Life LED light bulbs are designed to have a life of 1120 hours and packed in 25-unit packs. The manufacturer tends to set control limits to include 99.73% of the random variation in light bulb manufacturing process when it is in control. 20 packs of a large light bulb manufacturing process were sampled. Use the data for sampled packs in the table below to answer the following questions. Q1. What is the grand mean? Q2. What is the difference between the upper limit and the lower limit for the X chart? Q3. What is the lower limit for the R chart? Q4. Which statement is true? A. Sampling mean is shifting upward, but range is consistent. B. Sampling mean is constant, but dispersion is increasing- C. Sampling mean is shifting downward, but range is consistent. D. Both X chart and R chart show that the process is in control. Q5. What is the upper limit for the P chart? Q6. In P chart, which packs show variations due to assignable causes