I remember there were some in the high school textbooks. It may be a book with a purple cover at the back. I remember doing many such questions at that time. When she has a standard, it has a lot to do with how many things are bigger than it, and then the scope is irrelevant. Independence Test ~ Elective 2-3.

There are two classified variables, X and Y, with values ranging from {x 1, x2} and {y 1, y2}, and their sample frequency series table is: y 1 y2 total X1ABBA+BX2C DC+D total A+CB+D. When K2> is 3.84 1, there is a 95% probability that X is related to Y; K2>X and Y have a 99% probability correlation at 6.635.