$($b$)$ If the standard deviation for the $20$ basic cycles of the job is $2\mathrm{.}74($was found using a statistical calculator or Microsoft Excel$),$ determine if enough samples have been taken to be $95\%$ sure that the accuracy of the time study is within $5\%$ of the true mean value.

$n=[\{\frac{z}{a}\}\{\frac{s}{(\stackrel{}{x})}\}{]}^2=$

Enough samples? Yes.

No $q,$

$($c$)$ Find the average time to move the finished goods. $$ Since this job element only occurs with a frequency of $1$ in $10$ cycles, one$-$tenth of this time should be allocated to the overall job actual time.

Total actual time for job $=$

Actual average time for the assembly operation

$+(\frac{1}{10}{)}^{**}$ Actual average time for moving goods

Total actual time for job $=$

$($d$)$ The operator was judged to be working at a performance rating of $110\%.$ Find the normal time for the job.

Normal time Actual time