2 Proportions for Improve On-time Shipping Rate

Use 2 Proportions to demonstrate that the proportion of on-time shipping rate 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

On-time shipping rate is the proportion of orders that are received within the promised shipping window. To calculate on-time shipping rate, divide the total number of on-time shipments by the total number of shipments.

In this worksheet, On Time Before and On Time After represent the number of orders shipped on time 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.

`On Time Before`	`Total Orders Before`	`On Time After`	`Total Orders After`
1209	1522	1732	1844

How-to

Choose Solutions Modules > Functions > Supply Chain KPIs, then select Launch.
Under Delivery, select On-time shipping rate.
Select Improve on-time shipping rate, then click OK.
Select 2 Proportions, then click OK.
From the drop-down list, select Summarized data.
In Number of events, enter the number of on-time shipments before the process improvement as Sample 1. Enter the number of on-time 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 on-time shipments increased after the process change.
Click OK.

Tip

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