after a time study it was found that the average time for a

after a time study, it was found that the average time for a cycle of this operation was 5 minutes average and the standard deviation was .25 minutes. the particular operator stuidied was rated at 95 %. allowances for this job are 20 min personal, 15 min fatigue, and 25 minutes unavoidable delay, all based on an 8 hour shift. what are the standard time and the standard number of cycles per shift?

Solution

Average TIme=5mins

Standard Dev=.25 mins

Normal time=5*.95=4.75

Standard time=4.75/(1-.25)=4.75/.75=6.33

The standard time for this machinery operation would be set at 6.3 minutes, which is greater than the average cycle time observed. The average cycle time was adjusted for the rating factor (95%) and the allowance fraction (0.25)

Now in 8 hrs shift 20 min personal, 15 min fatigue, and 25 minutes unavoidable delay,

So net hrs are 7hrs

So standard number of cycles per shift=7*60/6.33=66.35