Substandard deviation The mean of a population \$(x_1,\dots,x_n)\$ is defined as \$\bar x=\frac1n\sum_{i=1}^n x_i\$. The (uncorrected) standard deviation of the population is defined as \$\sqrt{\frac1n\sum (x_i-\bar x)^2}\$. It measures how dispersed the population is: a large standard deviation indicates that the values are far apart; a low standard deviation indicates that they are close. If all values are identical, the standard deviation is 0.
Write a program or function which takes as input a (non-empty) list of non-negative integers, and outputs its standard deviation. But check the scoring rule, as this is not code golf!
Input/Output
Input/Output is flexible. Your answer must be accurate to at least 2 decimal places (either rounding or truncating). The input is guaranteed to contain only integers between 0 and 255, and to not be empty.
Scoring
To compute your score, convert your code to integer code points (using ASCII or whatever code page is standard for your language) and compute the standard deviation. Your score is the number of bytes in your code multiplied by the standard deviation. Lower score is better. You should therefore aim for code which at the same time (a) is short and (b) uses characters with close codepoints.
Here is an online calculator to compute your score (assuming you use ASCII).
Test cases
Input              | Output
77 67 77 67        | 5
82                 | 0
73 73 73           | 0
83 116  97 116 115 | 13.336

A word of caution about built-ins: if your language has a built-in, that's fine (and good for you if it only uses one character!). But make sure that it uses \$n\$ and not  \$n-1\$ as the denominator in the formula, or else your answer won't be valid.
MATL, score 65.30697
tYmhZs

Try it online! Or verify all test cases.
How it works
The built-in function Zs with its default arity (1 input, 1 output) computes the corrected standard deviation:
\$\sqrt{\frac 1 {n-1}\sum (x_i-\bar x)^2}\$
The uncorrected standard deviation can be obtained with the 2-input version of Zs: 1&amp;Zs, where 1 as second input means uncorrected. l or T could be used instead of 1 to reduce the score, but &amp; is very far from the other characters. 2$ or H$ could be used instead of &amp;, but $ is even farther.
So it is better to use the default version of Zs (corrected standard deviation) on the input with its mean appended. This increases the input length by 1 and contributes 0 in the numerator, which causes the corrected standard deviation to become uncorrected.
t     % Implicit input: numeric vector. Duplicate
Ym    % Mean
h     % Concatenate the input vector with its mean
Zs    % Corrected standard deviation