Question

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 0.02. If the desired confidence level is 99.7 percent, which of the following is the resulting UCL value for the line?

a. 0.39
b. 0.11
c. 0.06
d. 0.05
e. None of these

Answer 1

Answer:

Option E is correct one.

None of the options are correct. The correct answer is 0.08.

Explanation:

The Upper Control Limit (UCL) for a p-chart is calculated as,

UCL = P-bar + (Z x Sp)

where,

P-bar = Fraction defective = 0.05

Sp = Standard deviation = 0.01

Using standard normal table, for 99.7% confidence level,

Z = 3.00

Putting the given values in the above formula, we get,

UCL = 0.05 + (3.00 x 0.01)

UCL = 0.08