Answer: The missing value from the data set is 4.
Step-by-step explanation: Let's put it from least to greatest to figure it out...
2, 2, (4, 4,) 5, 8,
It would have to be 4, because 8 divided by 2 will equal 4. And because there's an even amount of numbers we have to add two numbers then divide it by 2.
4 + 4 = 8
8 ÷ 2 = 4
The mean is 4, and the missing value from the data set is 4.
I hope this helps!