Ch$.10$: Quality Control$\_$ Control Limits for Means $5($ pts$)-$Audio Products

At Audio Products, the time required to resolve a customer warranty claim si being reviewed. Historically, the process has had a standard deviation equal to $\mathrm{.}146.$ The mean of $39$ samples of n$=14$ is shown in the table below.

Sample Mean $3\mathrm{.}96$

$2345678$

$101112131415$

$16171819202122$

$23242526$

$27282930313233$

$34353637$

$3839$

a$.$

$3\mathrm{.}98$

$=$

$3\mathrm{.}863\mathrm{.}84$

$3\mathrm{.}87150\mathrm{.}15$

Calculate control limits with three$-$sigma limits$.$ Is the process in control? If the process is in control, why? fI the process si not ni control, why? Be specific.

Ch $10\_$Quality Control$\_$ Control Limits for Means