Sample Standard Deviation in JQ

Question

I've an array of numbers and I need to calculate the Sample Standard Deviation using jq.

Sample Standard Deviation formula (credits):

I've tried splitting the code into multiple pieces (length, mean), but none of my attempts worked because I don't know how to merge all the data into a single sqrt and map operation:

# Example of data input
_data="[73,73,76,77,81,100]"

_length=$(echo "$_data" | jq --raw-output 'length')
_mean=$(echo "$_data" | jq --raw-output 'add/length')

_standard_deviation=$(echo "$_data" \
                      | jq --raw-output \
                           --arg length "$_length" \
                           --arg mean "$_mean" \
                           '') # <- sqrt and map ?

echo "$_standard_deviation" # Should print 10.237187

Answer 1

This is how you do it:

(add / length) as $mean | (map(. - $mean | . * .) | add) / (length - 1) | sqrt

^{Online demo}