2-Sample t for Decrease Freight Cost Per Unit

Use 2-Sample t to demonstrate that average freight cost per unit decreases after a process improvement.

This example applies to the Supply Chain Module. For more information, go to www.minitab.com/supply-chain-module.

Example

Freight cost per unit is the total freight costs divided by the number of units shipped.

In this worksheet, Freight Cost/Unit ($) contains the freight cost per unit data. Process Change indicates whether the freight cost per unit is before or after a process improvement.

C1	C2-T
`Freight Cost/Unit ($)`	`Process Change`
1.78	Before
1.82	Before
2.36	Before
1.75	After
1.51	After
1.77	After

How-to

Choose Solutions Modules > Functions > Supply Chain KPIs, then select Launch.
Under Costs, select Freight cost per unit.
Select Decrease Freight Cost Per Unit, 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 freight cost per unit.
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 freight cost per unit has decreased after the process change.
Click OK.

Tip

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