What do you call the average of all data values

The average of all data values is called the mean, and can be found by adding all the values together then dividing the sum by the number of values.
Example: If the data values were 7, 3, 4, and 6, you'd add them all together:
7+3+4+6=20
then divide by the number of values
there are four values, so we divide the sum by 4
20/4=5 so in this case the mean would be five.

The correct answer is 7