The IRS is concerned with improving the accuracy of tax information given by its representatives over the telephone. Previous studies involved asking a set of $25$ 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 $76$ percent. Recently, IRS representatives have been receiving more training. On April $26,$ the set of $25$ tax questions were again asked of $20$ randomly selected IRS telephone representatives. The proportions of correct answers were:

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

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 $LC{L}_p$ equals

$($Enter your responses rounded to four decimal places. If your answer for $LC{L}_p$ is negative, enter this value as $0.)$