The manager of Stetson and Stetson Company is trying to develop a time standard for the powder filling and packing operation. This operation has five work elements, each of which is performed once every cycle. The allowance for each work element is 18 percent. The operation was studied for 20 cycles, and the following summary data were obtained: WorkElement Select Time(minutes) Standard Deviation(minutes) 1 2 3 4 5 0.40 0.20 0.31 0.15 1.25 0.021 0.011 0.018 0.005 0.085 a. Determine the standard time for the filling and packing operation. Assume the rating factor = 1.0.b. Determine the sample size necessary if the estimate of the select time for the work elements is to be within +-3 percent of the true mean 95 percent of the time.c. Is the sample size chosen to determine the standard time adequate? If not, how many additional cycles should be observed?
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
The manager of Stetson and Stetson Company is trying to develop a time standard for the powder filling and packing operation. This operation has five work elements, each of which is performed once every cycle. The allowance for each work element is 18 percent. The operation was studied for 20 cycles, and the following summary data were obtained:
| Work Element |
Select Time (minutes) |
Standard Deviation (minutes) |
|
1 2 3 4 5 |
0.40 0.20 0.31 0.15 1.25 |
0.021 0.011 0.018 0.005 0.085 |
a. Determine the standard time for the filling and packing operation. Assume the rating factor = 1.0.
b. Determine the
c. Is the sample size chosen to determine the standard time adequate? If not, how many additional cycles should be observed?
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