Question

A manager wants to build 3-sigmax-bar control limits for a process. The target value for the meanof 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

Answer 1

Upper limit=16

Lower limit=4

Explanation:

✓The Mean is given as 10 units with a

samples of size 9

✓standard deviation of the process is given as 6.

control limits for a process can be expressed as

Upper limit = x + 3 σ(√n)

lower limit = x - 3σ(√n)

If we substitute the values we have

Upper limit =

10+ (3 × (6)/ √9

10+ (3× 6/3)

= 16

lower limits=

=10 - (3 × (6)/√9

10 - (3× 6/3)

= 4