Generate random numbers with specific mean

9 次查看（过去 30 天）

Amr Ayman 2023-5-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1960034-generate-random-numbers-with-specific-mean

编辑： Matt J 2023-5-9

I want to generate matrix 4*4 of random integer values from 0 to 255, i used randi([0 255],4) but i want to generate it with specific mean for example 200 so i used:

z = randi([0 255],4)

z = z + (200 - mean2(z))

that did fix mean value but it could change min and max value of integers, How can i fix it ??!

2 个评论
显示无隐藏无

the cyclist 2023-5-8

编辑：the cyclist 2023-5-8

在 MATLAB Online 中打开

There are an infinite number of ways to generate random integers that have the following properties:

max = 255
min = 0
mean = 200

For example,

N = 1000000;

p = 200/255;

x = 255 * (rand(N,1) < p);

mean(x) % Will be equal to 200, within sampling error

ans = 200.2543

figure

histogram(x)

This distribution obeys the rules you have told us. And, as I said, there are infinite others. You need more specificity on the distribution.

Amr Ayman 2023-5-8

you're right, I should have been more specific about what i wanted but I couldn't explain what I needed more than that

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Matt J 2023-5-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1960034-generate-random-numbers-with-specific-mean#answer_1231294

编辑：Matt J 2023-5-8

在 MATLAB Online 中打开

You can use this FEX download

https://www.mathworks.com/matlabcentral/fileexchange/9700-random-vectors-with-fixed-sum?s_tid=srchtitle

m=4;n=4; targetMean=200;
z = randfixedsum(m*n,1,targetMean*m*n,0,255);
z=reshape(z,m,n);
mean(z(:))

ans =

200.0000

7 个评论
显示 5更早的评论隐藏 5更早的评论

Amr Ayman 2023-5-9

Thanks, I will look at it

Matt J 2023-5-9

编辑：Matt J 2023-5-9

There is a difference between

flip 10 coins, and on average get 5 tails
flip 10 coins, and always get 5 tails

There can be a difference, but note that the second always implies the first.

And yeah it generates real values not integer so i added floor after reshaping "which will make value of mean slightly change around 200 not to be always 200 :)) "

In fact, if you apply round() instead of floor(), I would expect the statistical average to remain at 200, even if the nonstatistical average mean(z(:)) does not remain perfectly at 200.

请先登录，再进行评论。

类别

MATLAB Language Fundamentals Matrices and Arrays Creating and Concatenating Matrices

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by