"the time needed for checking in at a hotel is to be investigated. historically, the process has had a standard deviation equal to .146. the means of 39 samples of n = 24 are sample mean sample mean sample mean sample mean 1 3.86 11 3.88 21 3.84 31 3.88 2 3.90 12 3.86 22 3.82 32 3.76 3 3.83 13 3.88 23 3.89 33 3.83 4 3.81 14 3.81 24 3.86 34 3.77 5 3.84 15 3.83 25 3.88 35 3.86 6 3.83 16 3.86 26 3.90 36 3.80 7 3.87 17 3.82 27 3.81 37 3.84 8 3.88 18 3.86 28 3.86 38 3.79 9 3.84 19 3.84 29 3.98 39 3.85 10 3.80 20 3.87 30 3.96

a. construct an x⎯⎯ -chart for this process with three-sigma limits. (do not round intermediate calculations. round your answers to 2 decimal places.) ucl lcl

b. is the process in control? yes no"