It's time to answer the main question! 
Note that we chose the **Mann-Whitney criterion** for this A/B test.

> Use `scipy.stats.mannwhitneyu(control_group_data, test_group_data, alternative = 'greater')`.

A/B test is one of the critical decisions when implementing something new in the IT sphere. It is the right time to get acquainted with this test!

In this section, we will learn some preparation things that are held before the A/B test.

In this section, we will perform our first A/B test. An easy version of the A/B test will help us to practice without difficulties!

It is time to meet the real A/B test. In this section, we will train ourselves using the knowledge we received during the two previous sections. After studying this section, you can say: 'I know what the A/B test is!'.

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