z distribution

[org.apache.commons.math3.distribution.TDistribution] Hello, I am writing a program for statistics and am don't have a very in depth knowledge of p value; I understand what it is so maybe it is that I don't understand cumulative probability and how it gets me a T Value. I've only taken...

What are the intervals of a grouped relative frequency distribution of a Z distribution? The range of the Z distribution is minus infinity to plus infinity and the relative frequencies are 0.5, 2, 13.5, 34, 34, 13.5, 2, and 0.5. Thank you! Dr. T