Sign Test in Excel using the QI Macros

When to Use the Sign Test

Use a Sign Test when you have paired data (e.g., before and after). The null hypothesis is that the before and after are the same.

Test Example

Imagine that you have 15 intersections where you record the number of accidents before and after the installation of a traffic control device. Enter the data and median into the QI Macros sign test (Anova Tools-Nonparametric):

The "before" accidents are in column A and the "after" in column B. The template calculates a p value.

Hypothesis Test Results: In this case, reject the null hypothesis, because the p value, 0.046 is less than alpha = 0.05. In other words, the traffic control device did reduce accidents.

Watch Non-parametric tests in Excel Video

The Sign Test is just one of the tests included in the QI Macros Statistical Process Control software. Other tests include:

• Overvew of all hypothesis tests in Excel
• Other Nonparametric tests in Excel in the QI Macros

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