3.3 Selecting and using information 87
what the graph means. Then, based on the
question, one must interpret the graph in the
required way.
The solution is quite simple and involves
subtracting the lowest point on any of the
bars from the highest point on any of the
bars. These values are (reading as accurately
as possible) 14° and 34°, so the total range
is 20°.Verbal information
In an inter-school hockey knockout
competition, there are initially 32 teams.
Teams are drawn by lots to play each other
and the winner of each match goes through
to the next round. This is repeated until there
are only two teams left, who play each other
in the final, and the winner gets a cup.
Matches have two halves of 20 minutes
each. If the teams are level at the end of
normal play, two extra 10-minute periods are
played. If it is still a draw, teams take penalty
shots at goal to decide the winner.
Chorlton High were eventually knocked out
in the semi-final (without extra time). In one
of the earlier rounds they had to play the two
extra periods before they won.
For how long in total had Chorlton High
played when they were knocked out?Activity
Commentary
There is a considerable mass of information
here, all presented as words. It must be read
carefully. The method of solution is not
difficult; the skill lies in choosing the correct
pieces of information and using them
appropriately. First we need to know how
many matches Chorlton High played. The first
round had 32 teams; subsequent rounds had
16, 8 and 4, which is when they were knocked
out – so they played 4 matches.totals are correct. All we have to do is check
each total in turn. Looking at the column
totals, we find that the first two (167 and 207)
agree with the entries by adding the three
numbers above them. However, the third one
does not agree with the entries above it, which
add up to 121.
We are not quite there yet; the wrong
number could be any of those in the ‘Jogging’
column. Repeating the procedure for the row
totals, we find that the second row (age 16–20)
adds up to 223. The error must be where the
wrong totals cross over. The incorrect figure is
the ‘45’ in the age 16–20 Jogging entry. It
should be 54; we know it should be 9 higher
because both the row and column totals were
9 too low. A transposition of the digits is a
common error when entering data.
Graphical information
The graph shows average monthly
temperatures for Bangladesh. The lower end of
the bar shows the average of the lowest daily
temperatures during the month and the top end
of the bar shows the average of the highest
daily temperatures during the month.Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0510152025303540Average temperature range (ºC)What is the difference between the lowest
average temperature and the highest average
temperature during the year?Activity
Commentary
There are two skills involved here. Firstly one
must understand the verbal description of