Question

A telephone customer service center wants to ensure that the majority of its customers’ calls are answered within a reasonable amount of wait time. Based on customer surveys, the company determined that the acceptable wait time that customers considered acceptable is between 10 and 45 seconds. A large sample of current customer calls was monitored. The average wait time was found to be 31 seconds with a standard deviation of 4.5 seconds.

What is the Capability Index for this process?

A. 1.30
B. 1.04
C. 1.56
D. 0.43

Answer 1

The Capability Index for this process is 1.04. The right answer is B

Step-by-step explanation:

According to the given data we have the following:

μ = 31 Seconds

USL = 45

LSL = 10

Standard deviation σ= 4.5

Therefore, in order to calculate the Capability Index for this process we would have to use the following formula:

Cpk=Min( USL-μ , μ- LSL)

3×σ 3×σ

Cpk=Min( 45-31 , 31- 10)

3×4.5 3×4.5

Cpk = Min ( 1.04,1.56) = 1.04

The Capability Index for this process is 1.04