Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math

Topic: simple statistics question
Replies: 2   Last Post: Mar 20, 2013 3:55 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
RGVickson@shaw.ca

Posts: 1,657
Registered: 12/1/07
Re: simple statistics question
Posted: Mar 20, 2013 3:55 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Wednesday, March 20, 2013 3:45:21 AM UTC-7, Thomas Plehn wrote:
> while(1) %Matlab code
>
>
>
> rr = rand(1,50); %sequence of 50 U(0,1) Values
>
>
>
> des = rand(1,50); %sequence of 50 U(0,1) Values
>
>
>
> diff = rr - des;
>
>
>
> %This are both decide statistics, a, b
>
> a = mean(rr);
>
> b = min(diff);
>
>
>
> disp(a-b); %their difference is nearly constant
>
> %but how is it distributed (mu,sigma)
>
>
>
> %and how does that depend on sequence length (n=50)
>
>
>
> %i think we can chose U(0,1) insted of U(a,b) without los of generality
>
> %(linear transformation of coordinates)
>
>
>
> end


In plain English, is the following a description of your problem? (Below, I have changed the notation, and assigned different symbols from yours. However, if I understand correctly what you want, the concepts are the same.)

We take two independent samples X = (X_1,X_2,...,X_n) and Y = (Y_1,Y_2,...,Y_n) from the distribution U(0,1). [n = 50 in your case.] You take the difference sequence Z = (X_1-Y_1, X_2-Y_2,...,X_n-Y_n) and compute a = mean(X), b = min(Z) = smallest of the differences X_i - Y_i. Finally, you look at D = a - b. You want the mean and variance of D, and maybe also the actual distribution.

You claim that D is "almost constant", by which I assume you do the above computations many times, using many different samples, and come up with results that differ by little.

Is all that a fair summary of what you are trying to say?




Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.