Sample mean
$$x_{v} = \frac{x_1\cdot m_1+x_2\cdot m_2+x3\cdot m3}{n}$$
x_v - sample mean (average)
x1, x2, x3 ... - sample values
m1, m2, m3 ... - frequencies of sample elements
n - number of sample elements
x1, x2, x3 ... - sample values
m1, m2, m3 ... - frequencies of sample elements
n - number of sample elements
Find
It is known that:
= 