Arithmetic mean of $$$5$$$, $$$7$$$, $$$12$$$, $$$12$$$

Find the arithmetic mean of $$$5$$$, $$$7$$$, $$$12$$$, $$$12$$$.

The arithmetic mean of data is given by the formula $$$\mu = \bar{x} = \frac{\sum_{i=1}^{n} x_{i}}{n}$$$, where $$$n$$$ is the number of values and $$$x_i, i=\overline{1..n}$$$ are the values themselves.

Since we have $$$4$$$ points, $$$n = 4$$$.

The sum of the values is $$$5 + 7 + 12 + 12 = 36$$$.

Therefore, the arithmetic mean is $$$\mu = \bar{x} = \frac{36}{4} = 9$$$.

The arithmetic mean is $$$\mu = 9$$$A.