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the mean and std value of a standard normal distribution

1 vue (au cours des 30 derniers jours)
yue li
yue li le 28 Août 2018
Commenté : yue li le 28 Août 2018
Hello,
I used matlab example https://www.mathworks.com/help/stats/normal-distribution.html
Compute the pdf of a standard normal distribution, with parameters µ equal to 0 and σ equal to 1. The mean value of norm should be 0, and the std value of norm should be 1.
Why the mean value of norm is 0.1636, and the std value is 0.1408?
Thanks in advance!
Yue
x = [-3:.1:3];
norm = normpdf(x,0,1);
>> norm_mean=mean(norm)
norm_mean =
0.1636
>> norm_std=std(norm)
norm_std =
0.1408
  2 commentaires
Adam
Adam le 28 Août 2018
You are taking the mean and std of the values on the y axis of the pdf, not the x axis, which is a fairly meaningless statistic.
yue li
yue li le 28 Août 2018
Modifié(e) : yue li le 28 Août 2018
Hello, Adam,
Thank you so much for your great help!
Yue

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Image Analyst
Image Analyst le 28 Août 2018
norm() is a built-in function so don't use that for your variable name.
Try using randn() and then using mean() and std() on that.
  1 commentaire
yue li
yue li le 28 Août 2018
Hello, Image Analyst,
Thank you do much for your reminding!
Yue

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