Question

5) Descriptive statistics. a) For each of the following classes, find: • lower class boundary upper class boundary class width class mid-point (i) 8-21 (4 marks) (ii) 1.54 - 3.47 (4 marks) b) The number of pizzas sold by a restaurant over the month of June was recorded and the data collected are shown below. 22 54 11 34 18 21 15 33 47 44 46 13 24 40 10 29 27 43 32 23 35 14 52 16 24 36 20 18 29 51 Construct an ordered stem and leaf diagram for this data. (4 marks) [Total 12 marks]

Answer 1

5)

a)

(i) 8 - 21

lower class boundary = 8

upper class boundary = 21

class width = (upper class boundary - lower class boundary) = (21 - 8) = 13

class mid-point = ((upper class boundary + lower class boundary) $\small \div$ 2) = ((21+8) $\small \div$ 2) = 14.5

(ii) 1.54 - 3.47

lower class boundary = 1.54

upper class boundary = 3.47

class width = (upper class boundary - lower class boundary) = (3.47 - 1.54) = 1.93

class mid-point = ((upper class boundary + lower class boundary) $\small \div$ 2) = ((3.47+1.54) $\small \div$ 2) = 2.505

b)

Stem and leaf diagram

Stem	Leaf
1	0 , 1 , 3 , 4 , 5 , 6 , 8 , 8
2	0 , 1 , 2 , 3 , 4 , 4 , 7 , 9 , 9
3	2 , 3 , 4 , 5 , 6
4	0 , 3 , 4 , 6 , 7
5	1 , 2 , 4