Descriptive Statistics of entire array

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Matthew Piccolo 2017-4-13

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回答： Andrii Mishchenko 2017-8-12

I am working on a project where I need to create a script that at one point returns the mean, median, mode, variance, standard deviation, minimum, maximum, and count of a user inputted array. The inputted array will either be a single column of an undetermined amount of numbers, or two columns of an undetermined amount of numbers.

To use the mean function as an example, if I have a matrix

x = [1,4;5,8;3,1;7,2;4,2];
then the mean function returns a mean of each column:
mean(x) = [4,3.4];

I need a mean of ALL the elements of the matrix. So a quick fix of this would be the mean2 function:

mean2(x) = 3.7;

This is great and returns exactly what I need, except I also need to find the median, mode, variance, etc. As far as I can tell, I can't just add the number 2 to the end of the functions that produce these statistical quantities to get the same result. So I need a way to either convert the user inputted matrix into a single column matrix (without losing the original matrix) and using the statistical analysis functions that way, or just a simple way to find these analyses of every single element of the array, not just the columns at single times.

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Answer 1

John D'Errico 2017-4-13

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在 MATLAB Online 中打开

So, you can't just compute

mean(x(:))
mode(x(:))

etc?

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Image Analyst 2017-4-14

在 MATLAB Online 中打开

and for the count (number of elements):

count = numel(x);

John D'Errico 2017-4-14

在 MATLAB Online 中打开

Or

prod(sixe(x))

will also work. But numel is better.

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Answer 2

Andrii Mishchenko 2017-8-12

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https://ww2.mathworks.cn/matlabcentral/answers/335306-descriptive-statistics-of-entire-array#answer_277804

Hello Dear, Matthew. You can use linear indexation in order to solve your problem. Let's consider your example with a matrix

x = [1,4;5,8;3,1;7,2;4,2];

If you will create a new matrix X = x(1:end) than you will obtain a row vector X containing all elements of your original matrix x. So you can perform a basic descriptive operations on this vector and calculations will be done considering all the values of the matrix x at the same time.

Cheers!