Question

Consider the following data of 10 averages and ranges on subgroups of size n=5 and the tensile strength of carbon component is recorded to assess the manufacturing process is being controlled. The sampling produces the following results (in pounds/square inch): 1 Lot No. X R 2 1511 1508 22 14 3 4 5 6 7 8 9 10 1522 1488 1519 1524 151915041 1500 1519 11 18 6 11 8 8 14 7 Construct R chart. Does the process appear to be in control? If not, explain why? Use table values as D3 = 0 and D4 = 2.114

Answer 1

given n=5= subgroup size Di 04 = 2:114 We know that R = Eri of sum Ranges Total groups. Total Obs? ol 119 11.9 We know that control limits for R-chart is UcL= R XD4 11.9x2.114 UCL = 25.1566 Ich= R XP3= 11.9xo = 0.00 LCL CLER 11.9 CamScanner

Y R-bar chart 30 28 26 UCL=25015 24 22+ 20 18 16 14 CL= 12 11.9 Range 16 8 6 4 2 LEGO 0 3 4 9 Lo 11 CScanned with VamScanner LOT Number

lower control In the above R-bar chart all the points are are fall between upper control limin't and limith. Interpretation - Therefore the given Statisticalith Process is in statistical Contrahner good process