I put a condensed version of this answer in the comments, but here is the full version.
Answer:
19.5
Step-by-step explanation:
The dots on the chart show the frequency of the numbers.
For example, 16 is only listed once while 22 is featured twice.
List all of the numbers:
16, 17, 17, 17, 17, 19, 19, 19, 19, 21, 22, 22, 23, 25
Now find the mean.
Mean = the average of all the numbers in a data set
To find the mean add all of the numbers, then divide by the number of numbers in the data set.
Add:
16 + 17 + 17 + 17 + 17 + 19 + 19 + 19 + 19 + 21 + 22 + 22 + 23 + 25 = 273
Divide:
There are 14 numbers, so divide by 14.
273/14 = 19.5
Therefore, the mean is 19.5