Answer:
Option a. 1.2 is the correct answer
Step-by-step explanation:
Given the data in the question;
sample size n = 10
sub group = 6
The average of sample means x" = 3.2
Average range value R' = 0.6
the value of UCL for the R-chart = ?
To get the value of UCL for the R-chart, we say;
[tex]UCL_R[/tex] = D₄ × R'
from table of constants "Tabular values for x-bar and range charts
for size 6, the factor for control limits for range Dâ‚„ = 2.004
so we substitute Â
[tex]UCL_R[/tex] = 2.004 × 0.6 Â
[tex]UCL_R[/tex] = 1.2024 ≈ 1.2 Â
Hence, Option a. 1.2 is the correct answer.