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
[tex]\bar{x}-3\dfrac{\sigma}{\sqrt{n}}\\\\=10-3\times \dfrac{6}{\sqrt{9}}\\\\=10-6\\\\=4[/tex]
Upper limit would be
[tex]\bar{x}+3\dfrac{\sigma}{\sqrt{n}}\\\\=10+3\times \dfrac{6}{\sqrt{9}}\\\\=10+6\\\\=16[/tex]
Hence, Third option is correct.