Question

Find the mean of:​ All prime numbers between $20$ and $40$​

Answer 1

All prime numbers between $20$ and $40$ are $23,29,31,37$.
Number of data values $=4$
$\text{Mean}=\frac{\text{Sum of all data values or observations}}{\text{Number of data values or observations}}$

$\Rightarrow \text{Mean}=\frac{23+29+31+37}{4}$

$=\frac{120}{4}=30$
Hence, the mean of all prime numbers in between $20$ and $40$ is $30$.