Mean

The arithmetic mean of $100$ observations is$24, 6$is added to each of the observations and then each of them is multiplied by $2.5$. Find the new arithmetic mean_____.

If the mean of first $n$ natural numbers is $\frac{5n}{8}$, then $n$ is

Positional mean is:

A survey is conducted in a class and the weight of the students is recorded. There are $40$ students in the class in which the ratio of boys to girls is $5 : 3$ and the average weight of the class is $35 Kg$. Later it is found that one student’s weight $36 kg$ is by mistake recorded as $63 Kg$. Which of the following will must change after correction. 

A. Mean 

B. Median 

C. Mode

If the mean of $4$ observations is $20$, when a constant $C$ is added to each observation, the mean becomes $22$. The value of $C$ is:

The mean of Five numbers is $18$. If one number is excluded, their mean is $16$. The excluded number is

The mean and median of $5$ observations are $9$ and $8,$ respectively. If $1$ subtracted from each observation, then the new mean and the new median will respectively be _____.

Prime numbers are the positive integers having only two factors $1$ and the integer itself.

$\mathrm{I}$. The mean of the first seven prime numbers is greater than their median.
$\mathrm{II}$. Mean is always greater than the median for prime numbers.

Which of the following statements is/are correct?