Getting an unknown error on calculating Standard Deviation.

I was trying to calculation using inbuilt Standard Deviation function but getting an error.

I ran the following code

load myfile.mat

std(v)

Error:

Error using var (line 74)

Invalid data type. First input argument must be single or double.

Error in std (line 59)

y = sqrt(var(varargin{:}));

[Atul Upadhyay]

I can see that the vector you are using has the int8 datatype in it and it contains values from 0 to 100. So, while calculating standard deviation there are chances of overflow.

Typecast the vector v to ‘double’ to get the desired output.

load myfile.mat;
v=double(v);
sd=std(v);

Refer to the following documentation to know more about datatypes in MATLAB.

https://in.mathworks.com/help/matlab/matlab_prog/integers.html

Answer 1

[Atul Upadhyay]

I can see that the vector you are using has the int8 datatype in it and it contains values from 0 to 100. So, while calculating standard deviation there are chances of overflow.

Typecast the vector v to ‘double’ to get the desired output.

load myfile.mat;
v=double(v);
sd=std(v);

Refer to the following documentation to know more about datatypes in MATLAB.

https://in.mathworks.com/help/matlab/matlab_prog/integers.html

Answer 2

[Bjorn Gustavsson]

Your variable v is a uint8. Try:

std(double(v))

HTH

Answer 3

[Hassan Eissa]

Compute the maximum value (max), minimum value (min), average value (mean), standard deviation (std) and the variance ( square of the standard deviation) of the variable 'signal

[Hassan Eissa]

[sample, signal]

Step 1 Compute the Statistics

This file contains a variable called signal that has 730 samples. Compute the maximum value (max), minimum value (min), average value (mean), standard deviation (std) and the variance ( square of the standard deviation) of the variable 'signal'.

% Create the variables below that represent the statistics of the variable signal

%

maxSignal =

minSignal =

avgSignal =

stdSignal =

varSignal =