Apps. and Interpretation for IBDP Maths Ebook 1 | Página 330

Your Practice Set – Applications and Interpretation for IBDP Mathematics
Exercise 93
1. Ravi and Yannick are trying to design a quiz on Statistics. They designed six questions
and they are going to comment on the relative difficulties of the questions. The table
below shows the ranking of six questions suggested by them, where 1 represents the most
difficult question and 6 represents the easiest question:
Question A B C D E F
Ravi 4 5 3 2 5 1
Yannick 4 6 2 4 1 3
(a)
Write down
(i)
the average equal ranks of the Question B and the Question E in Ravi’s
ranking;
(ii) the average equal ranks of the Question A and the Question D in
Yannick’s ranking.
[2]
(b) Find the Spearman’s rank correlation coefficient for the above data set.
[2]
(c) Comment on the conclusion of the result in (b).
[1]
2. An equestrian event is held in the Summer Olympics in 2012. The table below shows the
ranking of eight horse riders suggested by two judges, where 1 represents the highest
ranking and 8 represents the lowest ranking:
Horse rider A B C D E F G H
Judge 1 1 5 2 7 7 4 6 3
Judge 2 1 4 4 8 7 2 6 3
(a) Find the Spearman’s rank correlation coefficient for the above data set.
[4]
(b) Comment on the conclusion of the result in (b).
[1]
3. The number of goals of eight teams in a football league and their corresponding positions
are summarized in the following table:
Team A B C D E F G H
Number of
goals
68 62 32 49 15 45 46 28
Position in
the league
3 1 6 2 8 4 5 7
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