The histogram shows the lengths of a sample of European otters.

Find the class interval that contains the median.

The histogram shows the lengths of a sample of European otters.

Calculate an estimate for the mean length in $\mathrm{cm}$.

The histogram shows the waiting times for some customers at a supermarket.

Frequency density value at interval $0-40$ is $0.2$, $90-120$ is $0.7$, $120-180$ is $0.3$, $180-240$ is $0.1$

State the modal class.

The histogram shows the waiting times for some customers at a supermarket.

Frequency density value at interval $0-40$ is $0.2$, $90-120$ is $0.7$, $120-180$ is $0.3$, $180-240$ is $0.1$

Calculate an estimate for the mean waiting time in seconds rounded off to two decimal places.

The histogram shows the waiting times for some customers at a supermarket.

Frequency density value at interval $0-40$ is $0.2$, $90-120$ is $0.7$, $120-180$ is $0.3$, $180-240$ is $0.1$

Find the total number of customers.

The histogram shows the waiting times for some customers at a supermarket.

Frequency density value at interval $0-40$ is $0.2$, $90-120$ is $0.7$, $120-180$ is $0.3$, $180-240$ is $0.1$

Find an estimate for the number of customers who had to wait between $60$ and $90$ seconds, and also find who had to wait longer than $2$ minutes.