# Paired t-Test in Excel

## When to Use the Paired t-Test

In the constant quest to reduce variation and improve products, companies need to evaluate different alternatives. A t-Test using two paired samples compares two dependent sets of test data. It helps determine if the means (i.e., averages) are different from each other.

### Weight Loss Paired t-Test Example

If a diet claims to cause more than a 10 lb weight loss over a six month period, you could design a test using several individuals before and after weights. The samples are "paired" by each individual. You might want to know if the diet truly delivers greater than a 10 lb weight loss.

### To conduct a Paired t-Test Using QI Macros for Excel, follow these steps:

1. Input your data into Excel, then click and drag over it to select it

2. Next click on QI Macros Menu, Statistical Tools and select t-Test: paired two sample for means

3. QI Macros will prompt for a significance level (default = 0.05):

4. And a hypothesized mean difference (in this case 10 lbs):

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QI Macros paired t-Test macro will perform the calculations and interpret the results for you:

### What's Cool about QI Macros Paired t-Test?

Interprets the results for you: QI Macros will compare the p-value (0.429) to the significance level (0.05) and indicate that you "Cannot Reject the Null Hypothesis because p>0.05" and that the "Means are the same."

Draws a chart to help you visualize the results: QI Macros paired t test results include a box plot which helps you see the difference in means (color change line in the box) and the variation (height of the box and length of the whiskers.)

Interactive Results: QI Macros lets you change the significance level and Hypothesized Difference in Means to see what impact those changes have on your results. See red arrows in the image above.

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• Only \$279 USD - less with quantity discounts
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• Works Right in Excel
• Interprets Results for You
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