Source: $1950$ ASTM Manual on Quality Control of Materials, copyright American Society for Testing Materials, Reprinted with perm$$ssion$.$

The defect rate for a product has historically been about $7\mathrm{.}0\%.$ What is the upper control chart limit

$b$ if you wish to use a sample size of $20$ and $3-$sigma limits$?$

A$)0\mathrm{.}203$

B$)0\mathrm{.}241$

C$)0\mathrm{.}222$

D$)0\mathrm{.}186$