# OECD Gender wage gap data analysis 2 - Statistical Inference with Infer package, mean difference, calculation p-value with simulation based method UnsplashJames Wainscoatが撮影した写真

This post is following of the above post.

In the previous post I see mean of EMPLOYEE is 17.9 and mean of SELFEMPLOYED is 30.6.

Let's see whether the difference is statistically significant or not. Before doing statistical inference, let's do visualization.  I see SELFEMPLOYED Value is wider spreaded than EMPLOYEE Value.

Now, let's start statistial inference.
I will follow the methodology of B Inference Examples | Statistical Inference via Data Science (moderndive.com)

I calculate observed statistics, difference of mean, SELEMPLOYED mean - EMPLOYEE mean. So, 12.7 is the difference.

Then, I make null distribution of the difference. Now, I can do visualization for null distribution using visualize() function.  I see the center of stat is 0.

Let's see p-value on the above histogram.  I see the red vertical line is far away from the null distribution, it means p-value is very very small.

Let's calculate p-value. Calculate p-value is 0. So I can say the difference of mean between SELFEMPLOYED and EMPLOYEE is statistically significant.

That's it thank you!
Thank you Statistical Inference via Data Science (moderndive.com) !

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