Create a vector z with 1000 elements generated by the rand-function. The generated values must have a mean value of 0.5 (mean(0.5)). And a standard deviation of sqrt(1/100*12), (std(x)).

Question

Vetle Normann 2018-9-7

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418001-create-a-vector-z-with-1000-elements-generated-by-the-rand-function-the-generated-values-must-have

评论： Rik 2023-6-28

So my task is to determine mean of an random vector to be set to 0.5. And the set standard deviation to be sqrt(1/100*12)

2 个评论
显示无隐藏无

Adam 2018-9-7

And what have you done so far. I assume you have searched the Matlab help for functions such as 'rand' and followed the links from there to the other random number generation functions.

Rik 2023-6-28

What makes you think after almost 5 years that this question is unclear? Please provide an explanation in a comment.

I have removed your flag and will copy the question below.

Create a vector z with 1000 elements generated by the rand-function. The generated values must have a mean value of 0.5 (mean(0.5)). And a standard deviation of sqrt(1/100*12), (std(x)).

So my task is to determine mean of an random vector to be set to 0.5. And the set standard deviation to be sqrt(1/100*12)

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Cesar Antonio Lopez Segura 2018-9-7

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418001-create-a-vector-z-with-1000-elements-generated-by-the-rand-function-the-generated-values-must-have#answer_335862

在 MATLAB Online 中打开

Hi all

Here the code:

mu = 0.5;
sigma = 0.3464;
z = mu + randn(1,1000)*sigma
STDcalculated = std( z )
MuCalculated = mean( z )

3 个评论
显示 1更早的评论隐藏 1更早的评论

Vetle Normann 2018-9-7

Thank you! When I run loop on this script in Matlab STDcalculated and MuCalculated, the results are always close to 0.5 and 0.3463, but not the excact value. But is this as close as possible we get to 0.5 and 0.3464?

Cesar Antonio Lopez Segura 2018-9-7

在 MATLAB Online 中打开

Hi Vetle,

Using this values you can minimize your error:

mu = 0.50329141240781;
sigma = 0.347330944035507;

请先登录，再进行评论。

Answer 2

Torsten 2018-9-7

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418001-create-a-vector-z-with-1000-elements-generated-by-the-rand-function-the-generated-values-must-have#answer_335861

编辑：Torsten 2018-9-7

在 MATLAB Online 中打开

0.5*(a+b) = 0.5
1/12*(b-a)^2 = 0.12

Solve for a and b.

This will give you the interval [a b] for which you must generate uniformly distributed random numbers.

Then you can use the rand-function as

z=a+(b-a)*rand(1000,1)

Best wishes

Torsten.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Create a vector z with 1000 elements generated by the rand-function. The generated values must have a mean value of 0.5 (mean(0.5)). And a standard deviation of sqrt(1/100*12), (std(x)).

2 个评论
显示无隐藏无

采纳的回答

3 个评论
显示 1更早的评论隐藏 1更早的评论

更多回答（1 个）

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

另请参阅

类别

标签

Community Treasure Hunt

Create a vector z with 1000 elements generated by the rand-function. The generated values must have a mean value of 0.5 (mean(0.5)). And a standard deviation of sqrt(1/100*12), (std(x)).

2 个评论 显示 无隐藏 无

采纳的回答

3 个评论 显示 1更早的评论隐藏 1更早的评论

更多回答（1 个）

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

另请参阅

类别

标签

Community Treasure Hunt

2 个评论
显示无隐藏无

3 个评论
显示 1更早的评论隐藏 1更早的评论

0 个评论
显示 -2更早的评论隐藏 -2更早的评论