No topic, nothing. Suddenly a k will pop up.

If k is a random number, what distribution law should it obey and obey uniform distribution? Obey normal distribution? Obey student distribution?

From you

P (the square of k is greater than or equal to 6.635) is about 0.0 10.

Generally speaking, k should obey the normal distribution.

If it is.

P (the square of k is greater than or equal to 3.84 1) is about 0.025.

The calculation of this thing needs to calculate a formula in the diagram, as follows:

/2 1cn/ probability theory and mathematical statistics /gltj/fenbu/fenbu 1.gif

This formula is not easy to work out by hand.