Eric’s Cookie House sells chocolate chip cookies in shopping malls. Of concern is the number of chocolate chips in each cookie. Eric, the owner and president, would like to establish a control chart for the number of chocolate chips per cookie. He selects a sample of 15 cookies from today’s production and counts the number of chocolate chips in each. The results are as follows: 6, 8, 20, 12, 20, 19, 11, 23, 12, 14, 15, 16, 12, 13, and 12.
a. Determine the centerline and the control limits.
b. Develop a control chart and plot the number of chocolate chips per cookie.
c. Interpret the chart. Does it appear that the number of chocolate chips is out of control in any of the cookies sampled?