The difference of the highest and the lowest values in the data is called the ............

Draw a histogram to represent the following grouped frequency distribution:

Ages (in years)	Number of teachers
$20-24$	$10$
$25-29$	$28$
$30-34$	$32$
$35-39$	$48$
$40-44$	$50$
$45-49$	$35$
$50-54$	$12$

If the information gathered by an investigator is from an already existing source of data,then such information is called .........

The class mark of the class $70-90$ is ...........

The scores (out of $100$) obtained by $33$ students in a mathematics test are as follows:
$69, 48, 84, 58, 48, 73, 83, 48, 66, 58, 84$
$66, 64, 71, 64, 66, 69, 66, 83, 66, 69, 71$
$81, 71, 73, 69, 66, 66, 64, 58, 64, 69, 69$
Represent this data in the form of a frequency distribution table.

If the marks obtained by the $20$ students are $6, 4, 9, 5, 9, 3, 7, 7, 5, 6, 9, 4, 10, 10, 4, 3, 6, 7, 9, 9$,then the mode of this data is .............