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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, f and t tests, then 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):

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

To change the order of your Two-Sample t-Test results between the first and last columns:

1. Create your Two-Sample t-Test.
2. Then, in row 1 you have the option to update the "Column Order" by inputting value "1" (Column 1/Column 2) or "2" (Column 2/Column 1):



NOTE: Changing the order of your t-Test results will not change the order of the Box and Whisker output.

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.

Watch a QI Macros Paired t-Test Example in the Video

 

Learn More...

• One sample t-test
• Two-Sample t-Test

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Why Choose QI Macros Statistical Software for Excel?