A Quality Analyst Wants to Construct a Control Chart for Determining

Multiple Choice

A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected 1,000 units of output from each machine in random samples, with the following results: $$\begin{array} { c c } \text { Machine } & \text { Total Defectives } \\\hline \# 1 & 23 \\\# 2 & 15 \\\# 3 & 29 \\\# 4 & 13\end{array}$$
For upper and lower control limits of .026 and .014, which machine(s) , if any, appear(s) to be out-of-control for process proportion of defectives?

A) machine #3
B) machine #4
C) machines #3 and #4
D) machines #2 and #3
E) none of the machines