Question

The number of litres of petrol at a service station was recorded for each of the 60 days. The amounts are summarised in the following grouped frequency distribution.

Amount(L)	Frequency
Less than 10 000	6
10 000 –under 20 000	14
20 000 – under 30 000	21
30 000 - under 40 000	13
40 000 – under 50 000	6
Total	60

3.1 For these data estimate (to the nearest integer) the:

3.1.1 Mean (3)

3.1.2 Mode (3)

3.1.3 Median (3)

3.1.4 40th decile (3)

3.1.5 Standard deviation (5)

3.2 From the measures of central tendency calculated in 3.1, comment on the skewness of the above data. (2)

3.3 Draw an upward sloping ogive and indicate the lower quartile on the graph. (6)

Answer 1