Homework #$4-$ Mean quality control chart

An engineer at Bearkat Automotive wants to calculate the upper control limit $($UCL$)$ and lower control limit $($LCL$)$ for a process. Use the following table to calculate the UCL and LCL and determine if the process is in control. Use a Z value of $3\mathrm{.}0$ and a standard deviation of $10.$

Sample

Observation $1234$

A $54607080$

B $60506070$

C $70605060$

D $80706070$

$(5$ points$)$ Calculate the grand mean.

Sum of all observations$/$Total number of observations

$1024/16=$ Grand mean $64$

$(10$ points$)$ Calculate the upper and lower control limits

UCL $64+3\mathrm{.}0(10/4)=79$

LCL $64-3\mathrm{.}0(10/4)=49$

$(5$ points$)$ Draw the process in control and determine if it is in control?

The process is not in control because $2$ observations lie outside the control limits$.$

Observation D$(80)$ and Observation A $(80)$Homework #$4-$ Mean quality control chart

An engineer at Bearkat Automotive wants to calculate the upper control limit $($UCL$)$ and lower control limit $($LCL$)$ for a process. Use the following table to calculate the UCL and LCL and determine if the process is in control. Use a Z value of $3\mathrm{.}0$ and a standard deviation of $10.$

Sample

Observation $1234$

A $54607080$

B $60506070$

C $70605060$

D $80706070$

$(5$ points$)$ Calculate the grand mean.

Sum of all observations$/$Total number of observations

$1024/16=$ Grand mean $64$

$(10$ points$)$ Calculate the upper and lower control limits

UCL $64+3\mathrm{.}0(10/4)=79$

LCL $64-3\mathrm{.}0(10/4)=49$

$(5$ points$)$ Draw the process in control and determine if it is in control?

The process is not in control because $2$ observations lie outside the control limits$.$

Observation D$(80)$ and Observation A $(80)$