About uniform distribution pdf.....

I am trying to plot PDF of uniform distribution.... have problem in plotting pdf..

my code is as follows...

a=0;
b=2;
x=rand(1000,1);
y=unifpdf(x,a,b);
Plot(x,y)....

I know the mistake is in plotting ... i mean instade of x in plot what should i do ?

plot should be .5 till for (0,2) and 0 elsewhere........

[Torsten]

1. Write "plot" with a small "p".

2. Your x values are all between 0 and 1. To make a plot of the pdf, you should at least choose the x values to vary in between -1 and 3, say.

Best wishes

Torsten.

[rathod ujjval rameshbhai]

a=0;
b=2;
x = -1 + (3+1)*rand(100,1);
>> y=unifpdf(x,a,b);
>> plot(x,y);

The graf is still wrong why?

[rathod ujjval rameshbhai]

when I check the 100 values of y some are 0 and some are .5? it should be all .5 as the a=0;b=2;

[rathod ujjval rameshbhai]

If I do a=0;b=3; and take x from 0 to 3 then it is coming ok..... both pdf and cdf. BUT Why not for diffrent values of x and interval (a, b)? Is it nesessary to keep both x and a,b in the same interval?

[Walter Roberson]

-1 + (3+1)*rand is going to be in the range -1 + 4*0 = -1, up to -1 + 4*1 = 3. The entries that are from -1 to a are going to output 0, and the entries that are from b to 3 are going to output 0.

[rathod ujjval rameshbhai]

Thanks in short we have to keep range same for both (a,b) and x

[Torsten]

No.

a=0;
b=2;
x=linspace(a-1,b+1);
y=unifpdf(x,a,b);
plot(x,y)

Best wishes

Torsten.

[rathod ujjval rameshbhai]

Done..... thanks a lot Torsten.... But waht about rand()? Because linespace will generate values in sequence....

[Torsten]

unifpdf does only plot the analytically given PDF of the uniform distribution within a certain range. It does not work on randomly generated data or something similar.

If you want to plot the empirical CDF, you will have to use "histogram".

Best wishes

Torsten.