Maxx Industry is regularly supplying some critical parts to your assembly line. These parts are either good or defective. During each delivery a sample of 500 units is sampled and the number of defective units in the sample is noted. The average defect rate is 3.5%.
a. Develop the upper and lower control limits (z=3).
b. What is process capability index and what will be your objective in finding the process capability?
Answer
a) Upper lower limit
Standard deviation (z) = 3
Average = 3.5% of 500 which is 17.5
Multiply standard deviation by 3, which is 9,
Add the multiplied number to the average to get the upper-class limit,
"9+17.5 = 26.5" ,
Therefore upper-class limit is 26.5 Units.
Lower Class Limit
Multiply standard deviation by 3
"3*3=9"
Subtract nine from the average, which is 17.5
"17.5 - 9= 8.5"
Therefore the lower class limit is 8.5 units.
Process capability index is a set of calculations that determines whether, statistically, a system is able to meet a set of specification limits.
This process capability analysis will help ensure that the parts from Maxx Industry align with what my assembly requires.
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