A set contains seven numbers whose average is 12. The average of four greater numbers is 18 and the average of four smaller numbers is 8. Which of the followings is the value of one of the numbers?

If the variables $\displaystyle x$ and $\displaystyle z$ are so related that $\displaystyle z = ax + b$ for each where $\displaystyle a$ and $\displaystyle b$ are constant, then $\displaystyle \bar{z} = a\bar{x} + b$.

If the mean of the following distribution is $\displaystyle 6$, then the value of $\displaystyle P$ is: \displaystyle \begin{array}{|c|c|c|c|c|c|} \hlineX\displaystyle & 2 & 4 & 6 & 10 &P+5\displaystyle \\ \hlineF\displaystyle & 3 & 2 & 3 & 1 & 2 \\ \hline \end{array}

There are $\displaystyle n$ numbers. When 50 is subtracted from each of these number the sum of the numbers so obtained is $\displaystyle -10$. When 46 is subtracted from each of the original $\displaystyle n$ numbers, then the sum of numbers so obtained is 70. What is the mean of the original $\displaystyle n$ numbers?

Which measure is suitable for open-end classification?

$\displaystyle 50^{th}$ Percentile is equal to

Find the median of the following. Class: 0-10, 10-20, 20-30, 30-40, 40-50; Freq: 2, 3, 4, 5, 6