The IRS $is$ concerned with improving the accuracy $of$ tax information given $by$ its representatives over the telephone. Previous studies involved asking a set $of25$ questions $of$ a large number $of$ IRS telephone

representatives $to$ determine the proportion $of$ correct responses. Historically, the average proportion $of$ correct responses has been $74$ percent. Recently, IRS representatives have been receiving more training. $On$

April $26,$ the set $of25$ tax questions were again asked $of20$ randomly selected IRS telephone representatives. The proportions $of$ correct answers were:

$16,18,19,20,19,21,21,16,17,16,24,22,22,19,21,16,23,15,21,$ and $19.$

$a.$ What are the upper and lower control $limits$ for the appropriate $p-$chart for the IRS? Use $z=3.$

The $UC{L}_p$ equals and the $LC{L}_{p}LC{L}_{p}is$ negative, enter this value $as0.$

$b.Is$ the tax process $in$ statistical control?