Question

A manager wants to build 3-sigma x-bar control limits for a process. The target value for the mean of the process is 10 units, and the standard deviation of the process is 6. If samples of size 9 are to be taken, what will be the upper and lower control limits, respectively? 12 and 8 -8 and 28 4 and 16 16 and 4 8 and 12

Answer 1

Answer: Third option is correct.

Step-by-step explanation:

Since we have given that

Mean = 10

Sample size = 9

Standard deviation = 6

We need to find the upper and lower control limits.

so, Lower limit would be

$\bar{x}-3\dfrac{\sigma}{\sqrt{n}}\\\\=10-3\times \dfrac{6}{\sqrt{9}}\\\\=10-6\\\\=4$

Upper limit would be

$\bar{x}+3\dfrac{\sigma}{\sqrt{n}}\\\\=10+3\times \dfrac{6}{\sqrt{9}}\\\\=10+6\\\\=16$

Hence, Third option is correct.