I want to compute mean median and mode for the distribution from its c.d.f.

I want to compute mean median and mode for the distribution from its c.d.f.

\begin{array}{c|r}

p & .005 & .01 & .025 & .05 & .10 & .20 & .25 & .30 & .40 & .50 & .60 & .70 & .75 & .80 & .90 & .95 & .975 & .99 & .995\\

\hline

m=3 & .0717 & .1148 & .2158 & .3518 & .5844 & 1.005 & 1.213 & 1.424 & 1.869 & 2.366 & 2.946 & 3.665 & 4.108 & 4.642 & 6.251 & 7.815 & 9.348 & 11.34 & 12.84

\end{array}

Answer 1

[Jeff Miller]

The median is the value at p=0.50, which you already seem to have in your table. You can't really compute the mean and mode from the info in this table, but you can compute them from the known properties of the chisq(3). See, e.g., Wikipedia

[Jan]

I was trying these functions and I wanted to botain the 3 numbers in the pictture, but they are different:

>> a=(chi2pdf([0:0.01:1],3));

>> a(50)

ans =

0.2186

>> max(chi2pdf([0:0.01:1],3))

ans =

0.2420

mean(chi2pdf([0:0.01:1],3))

ans =

0.1979

>>

[Jeff Miller]

Jan, I think you might be misunderstanding what values you are getting from chi2pdf. This function returns values on the vertical y axis of your plots, but you are trying to compute mean, median, and mode values on the horizontal x axis as shown in your pictures.