Final answer:
To calculate the mean of a set of data, add up all the numbers in the set and then divide by the total number of numbers in the set.
Step-by-step explanation:
To calculate the mean of a set of data, you add up all the numbers in the set and then divide by the total number of numbers in the set. In this case, the set of data is 2, 4, 5, 11, and 5. Adding up these numbers gives us a sum of 27. Since we have 5 numbers in the set, the mean would be 27 divided by 5, which is 5.4.