1

The table shows the height of some plants. Work out the frequency density of the class $15 < h \le 25$.

Height, h (cm)	Frequency
0 < h ≤ 5	10
5 < h ≤ 15	10
15 < h ≤ 25	20
25 < h ≤ 30	10
30 < h ≤ 40	15

[2]

2

In a histogram, the class $10 < h \le 20$ has a frequency of 15. Work out the frequency density for this class. [2]

3

The table shows the time of some runners. Work out the frequency density of the class $20 < t \le 30$.

Time, t (min)	Frequency
0 < t ≤ 20	60
20 < t ≤ 30	10
30 < t ≤ 40	5
40 < t ≤ 50	5

[2]

4

A histogram is to be drawn for this data. Work out the height (frequency density) of the bar for the class $10 < w \le 15$.

Weight, w (kg)	Frequency
0 < w ≤ 10	15
10 < w ≤ 15	5
15 < w ≤ 20	5
20 < w ≤ 30	30
30 < w ≤ 50	50

[2]

5

The histogram shows the time of some runners. Estimate how many had a time between 40 and 50 min. [2]

6

The histogram and table show the same data. Use the histogram to find the missing frequency for the class $0 < t \le 5$.

Time, t (min)	Frequency
0 < t ≤ 5	?
5 < t ≤ 15	20
15 < t ≤ 25	15
25 < t ≤ 30	20
30 < t ≤ 40	15

[2]

7

The histogram shows the speed of some cars. Estimate how many had a speed between 5 and 40 mph. [3]

8

On this histogram each small square represents 5 runners. Estimate how many runners had a time between 10 and 20 min. [3]

9

A histogram is drawn for the weight of some parcels. The class $10 < w \le 30$ contains 60 parcels. Using the heights of the bars, estimate how many are in the class $40 < w \le 60$. [3]