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 = 22 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

103.80 20 3.87 30 3.96

a-1.

Construct anx-chart for this process with three-sigma limits. (Do not round intermediate calculations. Round your answers to 2 decimal places.)

UCL Not attempted

LCL Not attempted