Your specific error is with line 11:
awk 'BEGIN{sum+=$2}'
This is a line where awk is invoked, and its BEGIN block is specified - but you are already within a awk script, so you do not need to specify awk. Also you want to run sum+=$2 on each line of input, so you do not want it within a BEGIN block. Hence the line should simply read:
sum+=$2
You also do not need the lines:
x=sum
read name
the first just creates a synonym to sum named x and I'm not sure what the second does, but neither are needed.
This would make your awk script:
#!/bin/awk
### This script currently prints the total number of rows processed.
### You must edit this script to print the average of the 2nd column
### instead of the number of rows.
# This block of code is executed for each line in the file
{
sum+=$2
# The script should NOT print out a value for each line
}
# The END block is processed after the last line is read
END {
# NR is a variable equal to the number of rows in the file
print "Average: " sum/ NR
# Change this to print the Average instead of just the number of rows
}
Jonathan Leffler's answer gives the awk one liner which represents the same fixed code, with the addition of checking that there are at least 1 lines of input (this stops any divide by zero error). If