From primary school mathematics 1-6 grade, there is a chapter on statistics in each grade, but the content is deepening. The key to learning the "median" of statistical knowledge in the sixth grade depends on what you ask in statistics.

What is said upstairs is the previous textbook, and you may not be familiar with the current textbook. There is a chapter on statistics in grade one. Haha, if you don't believe me, you can look through the current textbooks.