Apps. and Interpretation for IBDP Maths Ebook 1 | Page 240

Your Practice Set – Applications and Interpretation for IBDP Mathematics
68
Paper 1 – Box-and-whisker plots
Example
The following box-and-whisker plot shows the number of emails sent by teachers in a
college on a particular week.
(a)
Find the inter-quartile range.
(b) One teacher sent p emails, where p � 42. Given that p is an outlier, find the
greatest value of p .
[2]
[4]
Solution
(a) The inter-quartile range
�53� 42
(A1) for correct formula
� 11
A1 N2
[2]
(b) p �42 � 1.5(11)
(M1)(A1) for correct inequality
p � 25.5
(A1) for correct value
Thus, the greatest value of p is 25. A1 N4
[4]
Exercise 68
1. The following box-and-whisker plot shows the number of parcels received by a group of
youngsters on a particular week.
The range and the inter-quartile range of the distribution are 24 and 6 respectively.
(a) Write down the values of a and b .
[2]
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