Question

A new industrial oven has just been installed at Piatt Bakery. To develop experience regarding the oven temperature, an inspector reads the temperature at four different places inside the oven each half hour starting at 8:00am. The last reading was at 10:30am, for a total of six samples. The first reading, taken at 8:00am, was 337 degrees Fahrenheit.(only the last 2 digits are given in the following table to make the computations easier.)

Time                                       Reading

                                   1                2              3           4

8:00am      37             43            44          40

8:30am                    45              42           43          40

9:00am                    43              49            40          44

9:30am                    45              43             47         41

10:00am                 35               48            49           63

10:30am                 45              42              46       49

A.) On the basis of this initial experience, determine the control limits for the range. (Round your intermediate calculations and final answers to 2 decimal places.)

LCL=___________

UCL=___________

Answer 1

	reading 1	reading 2	reading 3	reading 4	Range
8:00am	37	43	44	40	7
8:30am	45	42	43	40	5
9:00am	43	49	40	44	9
9:30am	45	43	47	41	6
10:00am	35	48	49	63	28
10:30am	45	42	46	49	7
				average	10.3333

average range R̅ =			10.3333
sample size n   =			4
for sample size n=4, criitcal value of constant D3=					0
for sample size n=4, criitcal value of constant D4=					2.282

lower control limit(LCL) =D3R̅ =0*10.3333=

0.00

upper control limit (UCL)=D4R̅ =2.282*10.3333 =

23.58