Enter your data for Stability Study

Stat > Regression > Stability Study > Stability Study

Complete the following steps to specify the columns of data that you want to analyze.

Select how to analyze batches. For more information, see Fixed versus random batches in Stability Study.
- No batch factor: Select this option if all the measurements are from the same source material.
- Batch is a fixed factor: Select this option to test for differences among batches when the data have samples from every batch.
- Batch is a random factor (mixed model): Select this option to test for differences among batches when the data have measurements from a random sample of batches.
In Response, enter the column of numeric data that you want to test, such as the concentration of a drug.
In Time, enter the column that contains the time each sample was taken.
(Optional) In Batch, enter the column that contains the batch each sample was taken from.
In Lower spec, enter the lowest acceptable value for the response. You can enter a lower specification limit, or an upper specification limit, or both. If you have two specification limits but only one limit is relevant to the shelf life, enter both limits, then press Options and select Use one spec limit to calculate shelf life.
In Upper spec, enter the highest acceptable value for the response.

In this worksheet, RunOrder contains the order that you collect the data. This column is not entered in the dialog. Drug% is the response and contains the concentration of a drug. Month is the time variable and indicates when the sample is collected. Batch indicates which batch the sample was collected from.

C1	C2	C3	C4
RunOrder	Month	Batch	Drug%
1	0	4	99.270
2	0	3	100.026
3	0	5	100.403
4	0	2	100.108
5	0	1	99.903