Final answer:
Adding up all the numbers gives us a sum of 80. Since there are 8 numbers in the list, we divide 80 by 8, which equals 10. The mean of the given list of numbers is 10.
Step-by-step explanation:
To find the mean of a list of numbers, you need to add up all the numbers in the list and then divide the sum by the total count of numbers.
In this case, the list of numbers is 15, 9, 12, 5, 15, 12, 4, and 8.
Adding up all the numbers gives us a sum of 80. Since there are 8 numbers in the list, we divide 80 by 8, which equals 10.
Therefore, the mean of the given list of numbers is 10.