Question

he accounts receivable department at Rick Wing Manufacturing has been having difficulty getting customers to pay the full amount of their bills. Many customers complain that the bills are not correct and do not reflect the materials that arrived at their receiving docks. The department has decided to implement SPC in its billing process. To set up control​ charts, 10 samples of 50 bills each were taken over a​ month's time and the items on the bills checked against the bill of lading sent by the​ company's shipping department to determine the number of bills that were not correct. The results​ were: Sample No. 1 2 3 4 5 6 7 8 9 10 No. of Incorrect Bills 9 2 14 1 3 2 3 4 9 0 ​a) The value of mean fraction defective ​(p overbar​) ​= nothing ​(enter your response as a fraction between 0 and​ 1, rounded to four decimal​ places).

Answer 1

0.094 or 9.4%

Explanation:

We have to compute the proportion of defective bills in each batch and then calculate a weighted average.

Let first construct a table like the one attached (see picture)

The value of the mean fraction defective is

`\large \bar p = (47)/(500)=0.094=9.4\%`