4.32.3 Can you answer these questions?

4.32.3.1 Is there a good explanation of the output of FeatureExtract anywhere?

https://mathematica.stackexchange.com/questions/154044/is-there-a-good-explanation-of-the-output-of-featureextract-anywhere

 
I have been looking at the official documentation of FeatureExtract, and I'm having a bit of difficulty interpreting the output--or understanding the reasons for some of the choices that were made.   ...
 

- asked by Shredderroy 1vote

4.32.3.2 How to work out sums symbolically?

https://mathematica.stackexchange.com/questions/153820/how-to-work-out-sums-symbolically

 
Intro 
 
Consider these two equal expressions of the variance 
 
$$\frac{\sum _{i=1}^n x(i)^2}{n}-\frac{\left(\sum _{i=1}^n x(i)\right){}^2}{n^2}$$ 
 
and 
 
$$\frac{\sum _{i=1}^n \left(x(i)-\frac{\sum  ...
 

- asked by Remi.b 1vote

4.32.3.3 Expectation value of standard deviation

https://mathematica.stackexchange.com/questions/153848/expectation-value-of-standard-deviation

 
I was trying to calculate the expectation value of the standard deviation, if I only take two data points into account. My code is the following: 
 
n[x_] = PDF[NormalDistribution[, ], x]; 
2[x1_,  ...
 

- asked by Glostas 1vote

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