Answer:
A. 20
Explanation:
To find the mean, first you have to add up all of the numbers in the set of data.
18+15+22+18+25+19+23= 140
Then you count how many numbers are in the set of data. In this case there are 7 numbers.
You then divide the sum of the numbers (140) by the amount of numbers (7)
140/7= 20.