2-Sample t for Decrease Average Call Length

Use 2-Sample t to demonstrate that average call length decreases after a process improvement.

This example applies to the Customer Contact Center Module. For more information, go to www.minitab.com/customer-contact-center-module.

Example

Average call length is the average length of time an agent spends on a call.

In this worksheet, Call Length contains the call length data. Process Change indicates whether the call length times are before or after a process improvement.

C1	C2-T
`Call Length`	`Process Change`
23.2	Before
19.8	Before
20.5	Before
19.0	Before
8.2	After
7.4	After

How-to

Choose Solutions Modules > Functions > Customer Contact Center KPIs, then select Launch.
Under Time Management, select Average call length.
Select Decrease average call length, then click OK.
Select 2-Sample t, then click OK.
From the drop-down list, select Both samples are in one column.
In Samples, enter the column that contains the call length data.
In Sample IDs, enter the column that indicates whether the data are from before or after your process improvement.
Click Options. In Alternative hypothesis, select Difference > hypothesized difference. The hypothesized difference defines your null hypothesis. By default, the hypothesized difference = 0. This one-sided test has greater power to detect whether the call length time has decreased after the process change.
Click OK.

Tip

For more information about this analysis, click Help in the main dialog box.