The marks obtained by $17$ students in a mathematics test (out of $100$) are given below:
$91, 82, 100, 100, 96, 65, 82, 76, 79, 90, 46, 64, 72, 68, 66, 48, 49$
The range of the data is:

The class marks of a frequency distribution are given as follows: $15, 20, 25, \ldots$ The class interval corresponding to the class mark $20$ is:

The following table shows a frequency distribution for the speed of cars passing through a particular spot on a highway:

Class interval $(km/h)$	Frequency
$30-40$	$3$
$40-50$	$6$
$50-60$	$25$
$60-70$	$65$
$70-80$	$50$
$80-90$	$28$
$90-100$	$14$

Draw the frequency polygon representing the above data without drawing the histogram.

The mean of $10$ observations is $48$. If each observation is divided by $3$,what will be the new mean?

The mean of the $10$ observations is $68$. If each observation is divided by $2$ and then $6$ is added to each result, find the mean of the new observations so obtained.

State whether each of the following statements is true or false:
$(1)$ The mean of the first four odd natural numbers is $4$.
$(2)$ The highest value of the data is called a range.
$(3)$ The mean of $30$ observations is $30$,then the sum of those observations is $60$.