2-Sample t for Decrease Supply Chain Cycle Time

Use 2-Sample t to demonstrate that average supply chain cycle time 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

Supply chain cycle time is the length of time to complete an order if inventory levels are zero. Supply chain cycle time includes the amount of time to order, fulfill, and receive the order.

In this worksheet, Number of Days contains the supply chain cycle times. Process Change indicates whether the supply chain cycle times are before or after a process improvement.

C1	C2-T
`Number of Days`	`Process Change`
58	Before
57	Before
56	Before
44	After
37	After
48	After

How-to

Choose Solutions Modules > Functions > Supply Chain KPIs, then select Launch.
Under Cycle Time, select Customer order cycle time.
Select Decrease supply chain cycle time, 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 of cycle time 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, choose 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 supply chain cycle time has decreased after the process change.
Click OK.

Tip

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