Telephone inquiries of 100 IRS \"customers\" are monitored daily at random. Inci
ID: 380667 • Letter: T
Question
Telephone inquiries of 100 IRS "customers" are monitored daily at random. Incidents of incorrect information or other nonconformities (such as impoliteness to customers) are recorded. The data for last week follow:
Telephone inquiries of 100 IRS "customers" are monitored daily at random. Incidents of incorrect information or other nonconformities (such as impoliteness to customers) are recorded. The data for last week follow Day No. of Nonconformities 7 15 23 4 5 16 a) Using 3 standard deviations, the c-chart for the nonconformities is: UCLc = nonconformities round your response to two dec malp acesExplanation / Answer
Number of days = 5
Sum of nonconfirmities = 7+15+23+22+16 = 83
C-bar = Sum of nonconfirmities / number of days
= 83/5
= 16.6
UCLc = C-bar + [Z(sqrt of C-bar)]
=C-bar + [3(sqrt of C-bar]
= 16.6 + [3(sqrt of 16.6)]
= 16.6 + (3 x 4.07)
= 16.6 + 12.21
= 28.81
(Note : As we use a three Standard deviation, the value of Z = 3)