Question

Convert data into grouped frequency distribution:
$3,5,1,2,3,2,2,1,6,9,5,3,9,2$

Answer 1

First the arrange the data in order,
$1,1,2,2,2,2,3,3,3,5,5,6,9,9$
The largest number $=9$
The smallest number $=1$
Range $=$ largest number $-$ smallest number $=9-1=8$
Hence, we shall calculate an approximate group size, by dividing the range by how many groups you would like.
If we want $4$ groups, then Divide range with number of groups $=\frac{8}{4}=2$
The class interval width is $2$. Start from $0$.

So, the grouped data will be as follows.

Cass interval	Frequency
$0-2$	$2$
$2-4$	$7$
$4-6$	$2$
$6-8$	$1$
$8-10$	$2$