  ### Home > CCA2 > Chapter 12 > Lesson 12.2.2 > Problem12-116

12-116.

At the Bright Idea Lighting Company $10$ flashlights are sampled each hour to determine whether the manufacturing process is in control. The UCL is $0.10$ defective, and the LCL is $0.05$ defective.

1. Create a process control chart for the following hours.

 Hour proportion defective $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$ $11$ $12$ $13$ $0.06$ $0.08$ $0.09$ $0.06$ $0.05$ $0.08$ $0.08$ $0.07$ $0.11$ $0.10$ $0.05$ $0.07$ $0.04$
 Hour proportion defective $14$ $15$ $16$ $17$ $18$ $19$ $20$ $21$ $22$ $23$ $24$ $25$ $0.08$ $0.08$ $0.09$ $0.08$ $0.09$ $0.09$ $0.08$ $0.09$ $0.10$ $0.06$ $0.05$ $0.05$ checksum $1.88$

Place the 'hours' on the $x$-axis and the 'proportion defective' on the $y$-axis. Scale the $y$-axis from $0.05$ to $0.10$.

2. As a quality control engineer for Bright Idea, what do you report about the process control?

Draw a centerline at $y = 0.075$ on your graph.
Comment on how close/far the points are relative to the centerline.
What about several points in a row staying above/below the centerline?