Problem
Find the mean of: 12, 15, 18, 21, 24
📝Step-by-Step Solution
1
Understand what mean is
The mean is the average. It's found by adding all values and dividing by how many values there are.
Mean = Sum of all values / Number of values
2
Add all the numbers
12 + 15 + 18 + 21 + 24 = 90
Sum = 90
3
Count the numbers
There are 5 numbers in the data set.
Count = 5
4
Divide sum by count
Mean = 90 ÷ 5 = 18
Mean = 90 ÷ 5 = 18
✅Final Answer
Mean = 18
The mean represents the "center" of the data if all values were equal. Notice that 18 is literally the middle number here! The mean is affected by outliers (extreme values), so sometimes median is more representative.
Ready to Practice Mean, Median, Mode?
Generate a personalized practice test with MathQuizily. Get instant PDF downloads with answer keys.