Martha$$s Wonderful Cookie Company makes a special super chocolate$-$chip peanut butter cookie. The company would like the cookies to average eight chocolate chips apiece. Too few or too many chips distort the desired cookie taste. Twenty samples of five cookies each during a week have been taken and the chocolate chips counted. The sample observations are shown below. Construct X$-$bar and R charts for this process. The $3\backslash$sigma upper control limit for average chocolate chips per cookie is closest to $9\mathrm{.}73.$

Martha$$s product specs for super chocolate$-$chip peanut butter cookies is $8$ chocolate chips per cookie $+/-2$ chips. Use these product specifications limits and the control limits calculated above to calculate the process capability ratio. The process capability ratio is closest to:

$0\mathrm{.}52$

$0\mathrm{.}81$

$1\mathrm{.}23$

$2\mathrm{.}23$

I originally chose $0\mathrm{.}52,$ but it was marked incorrect. Here is the feedback I received: Recalculate. This is the process capability index, not ratio.