1. A time study analyst timed an assembly operation for 30 cycles and then computed the average time per cycle, which was 16.25 minutes. The analyst assigned a performance rating of 0.86, and decided that an appropriate allowance was 12 percent. Assume the allowance factor is based on the workday, determine the following:

(a) the observed time (OT);

(b) the normal time (NT); and

(c) the standard time (ST).

2.A time study analyst wants to estimate the number of observations needed to achieve a specified maximum error, with a confidence of 90 percent. A preliminary study yielded a mean of 6.7 minutes and a standard deviation of 1.3 minutes. Determine the total number of observations needed for the following two (2) cases:

(a) A maximum error of 16 percent of the sample mean.

(b) A maximum error of 30 minute

3An analyst has been asked to estimate the proportion of time that a turret lathe operator spends adjusting the machine, with a 0 percent confidence level. Based on previous experience, the analyst believes the proportion will be approximately 30 percent.

(a) If the analyst uses a sample size of 600 observations, what is the maximum possible error associated with the estimate?

(b) What sample size would the analyst need to have the maximum error be no more than 16 percent?

p.30 z = 2.00 for 95.5 percent confidence