averaging grouped values, rounding upwards

data.sh

#!/usr/bin/env bash
unset key
cat data.csv |      # reads from data.csv
tail -n +2 |        # removes first line
tr -d ' ' |         # removes all spaces
cut -d ',' -f1,3 |  # takes first and third field

# from here on this program:
# calling the right-hand field (string) the key,
# and the left-hand field (positive integers) the values,
# groups by key, returning a rounded-upwards average of the values,
# as, in order, key and the average, separated by a tab character

tr ',' '\t' |  # replaces commas with tabs
uniq -f 1 --group=append |
# ↑ groups by key, by appending a blank line after each key-group
while read -r value lkey
  # fits each group in a single
  # "key value value value..." line
do
    if [[ ! -z $value ]]
    then
	if [[ ! -v key ]]
	then
	    key=$lkey; echo -ne "$key"
	elif [[ $lkey != $key ]]
	then
	    exit 13
	fi
	echo -ne "\t${value}"
    else
	unset key
	echo
    fi
done |
awk \
    # averages the values in each line,
    # rounding the average up.
    '{ sum=0; num=0;
       for (i=2;i<=NF;i++)
       	   {sum+=$i; num++ } ;
       sum=sum/num ;
       num=int(sum) ;
       sum=(sum>num ? num+1 : num) ;
       printf "%s\t%d\n", $1, sum }'