<human>:  I have a question about a/b testing. When you are testing a new feature, how do you decide which version of the feature to use?
<bot>: You can use a statistical test to decide which version is better. The test is called a chi-square test. It is a test that compares the difference between two groups. In this case, the groups are the two versions of the feature. The test will tell you if the difference between the two versions is statistically significant.