If the mean of the numbers $27, 31, 89, 107, 156$ is $82$,what is the mean of the numbers $130, 126, 68, 50, 1$?

Which of the following averages is most affected by extreme observations?

The average age of a teacher and three students is $20$ years. If all the students are of the same age and the difference between the teacher's age and the age of one of the students is $20$ years,find the teacher's age in years.

The relation between the median $M$,the second quartile ${Q_2}$,the fifth decile ${D_5}$,and the $50^{th}$ percentile ${P_{50}}$ of a set of observations is:

If the arithmetic mean of the numbers $x_1, x_2, x_3, ..., x_n$ is $\bar{x}$,then the arithmetic mean of the numbers $ax_1 + b, ax_2 + b, ax_3 + b, ..., ax_n + b$,where $a$ and $b$ are two constants,would be:

The mean of discrete observations $y_1, y_2, \ldots, y_n$ is given by: