Answer:
About 11.96
Explanation:
The mean of a data set is basically the average.
To find the average, add up all of the data values and then divide by the amount of numbers there are.
First, add the numbers.
3 + 19 + 21 + 6.8 + 9.3 + 21.7 + 2.9 = 83.7
There are 7 numbers in this data set so divide 83.7 by 7
83.7/7 = 11.95714285714286
Round this number to the nearest hundreth, to get 11.96
So, the mean of this data set is 11.96
I hope this helps!