If the sum of square of the values equals to 3390, Number of observations are 30 and Standard deviation is 7, what is the mean value of the above observations?

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