$4.$ The Dorben Company is using the work sampling technique to establish standards

for its data entry clerks. The pool has six clerks, each of whom works a $40-$h week.

Over a four$-$week period, $1,700$ random simultaneous observations of all six clerks

were made. During the study period, the clerks produced $9,001$ entries. Of the

random observations, $1,225$ showed that data entry was taking place. Assuming a

$20$ percent allowance and an average data entry rating of $85$ percent, calculate the

hourly standard per entry.

$5.$ How many observations should be recorded in determining the allowance for

personal delays in a forge shop, if it is expected that a $5$ percent personal allowance

will suffice, and if this value is to remain between $4$ and $6$ percent across $95$ percent

of the time?

$6.$ To get $65$ percent precision on work that is estimated to take $80$ percent of the

workers$$ time, how many random observations are required at the $95$ percent confidence level?

$7.$ If the average handling activity during a $10-$day study is $82$ percent and the number

of daily observations is $48,$ what is the confidence interval for each day$$s percentage activity?

$8.$ The following data were collected by an intern working at the Mole Hill Ski Resort

regarding the efficiency of the V$-8$ Ford engine that was used to power the rope tow

for the bunny slope. Managers would like to know how many hours of service they

can expect to achieve out of their obviously failing engine out of a typical $16-$h

skiing day. After studying the data, you can state with $95$ percent confidence that

the engine will be able to run for $\_\_\_\_\_\_\_\_\_\_\_$ h $6\_\_\_\_\_\_\_\_\_\_\_$ h of a $16-$h day.

Running on $8$ cylinders

Running on $7$ cylinders

Running on $6$ cylinders

Not running, engine clogged

$9.$ Data from an $8-$h work sampling study are shown below.

a$.$ What percentage of the time is the machine running?

b$.$ What percentage of the time is the machine broken?

c$.$ What is the limit of accuracy of this study for a $50\mathrm{.}05?$

d$.$ What is the $95$ percent confidence interval of the machine running?

e$.$ Your manager says that the range in part d is unacceptably large. She would

like to narrow the range down to $61$ min of running time. How many observations should you collect to achieve this?

fre$76361\_$ch$14\_555-584.$indd $58123/11/127$:$00$ PM

$582$ CHAPTER $14$

Running

Idle

Broken

Out of stock

Other