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p value Calculator in Excel

Calculating a p value is Easy - Interpreting It is Hard

One subject that inspires much head-desk banging is interpreting the results of statistical hypothesis tests. It seems that students easily learn how to perform the calculations required by a given test but get hung up on interpreting the results.

- Student Post on Cross Validated

Any Statistical Software package, including Excel, can calculate p values. However, very few will help you interpret the results. Fortunately, QI Macros Add-in for Excel does both.

QI Macros Calculates p values and Interprets Them for You

A p value (probability value) is used in hypothesis testing to determine the statistical significance of what a sample is telling you about a population.

The p-value is a number between 0 and 1 and is interpreted against a desired level of significance (.05) as follows:

Value	Strength of Evidence	Reject the Null Hypothesis?	Means and Variances
small p-value less than 0.05	Strong evidence against the null hypothesis	Reject the null hypothesis	Means or Variances are not the same Means are Different
large p-value greater than 0.05	Weak evidence against the null hypothesis	Cannot reject the null hypothesis	Means or Variances are the same Means are Not Different
p-value = .05 or is close to it	Evidence does not point strongly either way	Can either reject or cannot reject the null hypothesis	Means or Variances may be the same

Note: .05 and .01 are the most common levels of significance used.

Example of a QI Macros t test and p value calculation

QI Macros compares the p-value to the significance level for you and translates that into whether you can reject the null hypothesis or cannot reject the null hypothesis (accept the null hypothesis). It further interprets whether the means are equal (the same/are not different) or not equal (not the same/are different.)

QI Macros results are also interactive and let you change the significance level and Hypothesized Difference in Means to see what impact those changes have on your results. See areas outlined in red in the results image above. 

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Why Choose QI Macros Statistical Software for Excel?