The ............. of each class of frequency distribution is shown on the $x$-axis,in a frequency polygon.

The mean of the data: $2, 8, 6, 5, 4, 5, 6, 3, 6, 4, 9, 1, 5, 6, 5$ is given to be $5$. Based on this information,is it correct to say that the mean of the data: $10, 12, 10, 2, 18, 8, 12, 6, 12, 10, 8, 10, 12, 16, 4$ is $10$? Give reason.

Convert the given frequency distribution into a continuous grouped frequency distribution:

Class interval	Frequency
$150-153$	$7$
$154-157$	$7$
$158-161$	$15$
$162-165$	$10$
$166-169$	$5$
$170-173$	$6$

In which intervals would $153.5$ and $157.5$ be included?

Draw a histogram to represent the following grouped frequency distribution:

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

The mean of the observations $x+5$,$x+3$,$x+11$,and $x+1$ is ..........

Mode of the data $15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15, 17, 15$ is