1. The problem is to find the formula for the mean of a set of numbers. 2. The mean, also called the average, is a measure of central tendency that summarizes a data set with a single value. 3. The formula for the mean of $n$ numbers $x_1, x_2, \ldots, x_n$ is: $$\text{Mean} = \frac{x_1 + x_2 + \cdots + x_n}{n} = \frac{1}{n} \sum_{i=1}^n x_i$$ 4. This means you add all the numbers together and then divide by how many numbers there are. 5. Important rules: - Make sure to include all numbers in the sum. - The number of terms $n$ must be the count of all numbers. - The mean gives a central value but can be affected by very large or very small numbers (outliers). 6. Example: For numbers 2, 4, 6, 8, 10, the mean is: $$\frac{2+4+6+8+10}{5} = \frac{30}{5} = 6$$ 7. So the mean of these numbers is 6.