The mean of the first ten natural numbers is ........

The times,in seconds,taken by $150$ athletes to run a $110\, m$ hurdle race are tabulated below:

Class (seconds)	$13.8-14.0$	$14.0-14.2$	$14.2-14.4$	$14.4-14.6$	$14.6-14.8$	$14.8-15.0$
Frequency	$2$	$4$	$5$	$71$	$48$	$20$

The number of athletes who completed the race in less than $14.6\, s$ is:

The mean and median of a frequency distribution are $72.5$ and $73.9$ respectively. Then,the mode of the data is $\ldots \ldots \ldots . . .$

In the formula $\bar{x} = A + \frac{\Sigma f_{i} d_{i}}{\Sigma f_{i}}$,$d_{i} =$ .........

Find the mean of the following data:

Class	$200-299$	$300-399$	$400-499$	$500-599$	$600-699$	$700-799$	$800-899$
Frequency	$3$	$61$	$118$	$139$	$126$	$151$	$2$

In the formula $\bar{x} = \frac{\Sigma f_{i} x_{i}}{n}$,$f_{i}$ represents ..........