The Robin Hood Bank has noticed a decline in daily deposits. The average daily deposit has been running at $109 million with an average range of $15 million over the past year. The deposits for the past six days have been 110, 102, 96, 87, 115, and 106.

a. What are the CL, UCL, and LCL for the and R charts based on a sample size of six days?

b. Compute an average and range for the sample that consists of the past six days. Do the figures for the past six days suggest a change in the average or range from the past year?