2 Proportions for Improve Damage-free Delivery

Use 2 Proportions to demonstrate that the proportion of damage-free delivery increases after a process improvement.

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

Example

Damage-free delivery is the proportion of orders that are delivered without damage.

In this worksheet, Damage Before and Damage After represent the number of orders delivered with damage before and after a process improvement. Total Orders Before and Total Orders After represent the total number of shipped orders before and after the process improvement.

With summarized data, you enter the data values instead of the column identifiers.

`Damage Before`	`Total Orders Before`	`Damage After`	`Total Orders After`
53	987	32	844

How-to

Choose Solutions Modules > Functions > Supply Chain KPIs, then select Launch.
Under Quality, select Damage-free delivery.
Select Improve damage-free delivery, then click OK.
Select 2 Proportions, then click OK.
From the drop-down list, select Summarized data. To demonstrate that the proportion of damage-free delivery increases after a process improvement, we look at the proportion of damaged shipments before and after a process improvement to test whether the proportion of damaged deliveries decreases.
In Number of events, enter the number of damaged shipments before the process improvement as Sample 1. Enter the number of damaged shipments after the process improvement as Sample 2.
In Number of trials, enter the total number of shipments before the process improvement as Sample 1. Enter the total number of shipments after the process improvement as Sample 2.
Select 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 proportion of deliveries with damage decreased after the process change.
Click OK.

Tip

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