Chapter $7$ Question $3$ Page $332$

A time study was conducted on a job that contains four elements.

The observed time and performance ratings for six cycles are shown in the following table.

OBSERVATIONS $($minutes per cycle$)$

Element

Performance

Rating

$1$

$2$

$3$

$4$

$5$

$6$

$1$

$\mathrm{.}90$

$0\mathrm{.}44$

$0\mathrm{.}50$

$0\mathrm{.}43$

$0\mathrm{.}45$

$0\mathrm{.}48$

$0\mathrm{.}46$

$2$

$\mathrm{.}85$

$1\mathrm{.}50$

$1\mathrm{.}54$

$1\mathrm{.}47$

$1\mathrm{.}51$

$1\mathrm{.}49$

$1\mathrm{.}52$

$3$

$1\mathrm{.}10$

$0\mathrm{.}84$

$0\mathrm{.}89$

$0\mathrm{.}77$

$0\mathrm{.}83$

$0\mathrm{.}85$

$0\mathrm{.}80$

$4$

$1\mathrm{.}00$

$1\mathrm{.}10$

$1\mathrm{.}14$

$1\mathrm{.}08$

$1\mathrm{.}20$

$1\mathrm{.}16$

$1\mathrm{.}26$

a$.$ Determine the average cycle time for each element

OBSERVATIONS $($minutes per cycle$)$

Element

$1$

$2$

$3$

$4$

$5$

$6$

Average

$($OT$)($min$.)$

$1$

$0\mathrm{.}44$

$0\mathrm{.}50$

$0\mathrm{.}43$

$0\mathrm{.}45$

$0\mathrm{.}48$

$0\mathrm{.}46$

$2$

$1\mathrm{.}50$

$1\mathrm{.}54$

$1\mathrm{.}47$

$1\mathrm{.}51$

$1\mathrm{.}49$

$1\mathrm{.}52$

$3$

$0\mathrm{.}84$

$0\mathrm{.}89$

$0\mathrm{.}77$

$0\mathrm{.}83$

$0\mathrm{.}85$

$0\mathrm{.}80$

$4$

$1\mathrm{.}10$

$1\mathrm{.}14$

$1\mathrm{.}08$

$1\mathrm{.}20$

$1\mathrm{.}16$

$1\mathrm{.}26$

b$.$ Find the normal time for each element

Element

NT

$($OT x PR$)$

$1$

$2$

$3$

$4$

c$.$ Assuming an allowance factor of $15$ percent of job time, compute the standard time for this job.

Standard Time $=$