You want to determine the upper control line for a p-chart for quality control purposes. You take several samples of a size of 100 items in your production process. From the samples, you determine the fraction defective is 0.05 and the standard deviation is 0.01. If the desired confidence level is 99.7 percent, what is the resulting UCL value for the line?

0.08

Explanation:

"p" bar is the fraction defective.

"sp" is the standard deviation.

"n" is the sample size.

"z" is the number of standard deviations for a specific confidence.

And z = 3 (99.7 percent confidence) or

z = 2.58 (99 percent confidence) is used.

In this problem, p bar is 0.05 and sp = 0.01

thus, 0.05 + (3 x 0.01) = 0.08

The resulting UCL value for the line is 0.08.