Answer: 18.5
Step-by-step explanation:
The way to find the mean of a data set is to add up all the values and then divide by the number of data points.
First add up all of the values. 12+14+22+14+18+23+42+13+9+19+22+14=222.
Now count how many data points there are. There are 12 data points.
Finally, divide the sum you got by the number of data points. 222/12=18.5
