Question

If there are 4 total defects from 8 samples, each sample consisting of 20 individual items in a production process, which of the following is the fraction defective (or value for p-bar) that could be used in a p chart for quality control purposes?

a.0.025
b.0.5
c.2.5
d.1.0

Answer 1

The fraction defective, or value for p-bar, for use in a p chart for quality control is 0.025, calculated by dividing the total number of defects (4) by the total number items (160) inspected.

Step-by-step explanation:

To calculate the fraction defective, also known as the value for p-bar, for use in a p chart for quality control, we first need to find the total number of defects and divide it by the total number of items inspected. In this case, there are 4 defects from 8 samples, with each sample consisting of 20 individual items.

To find the total number of items inspected, we multiply the number of samples by the number of items per sample:

• 8 samples × 20 items/sample = 160 items

Next, we divide the total number of defects by the total number of items:

• 4 defects / 160 items = 0.025

Therefore, the value of p-bar for the p chart is 0.025.