Answer:
Average range(R-bar) = Sum of the sample range for each sample/number of samples = (9+8+1+8+7) /5 = 33/5 = 6.6
Sample size = 8
For a sample size of 8 the factors for control limit for range (D3) = 0.136 (obtained from table of constraints for x-bar and R chart
LCL = R-bar × D3 = 6.6 × 0.136 = 0.90
Step-by-step explanation: