Page 26 - Math SL HB Sem 3

Watch Out
The line of best fit must pass through the mean point (t, r) and have approximatety an equal
number of points lying above and below the line.

\. Example:

A group of students took their history and maths tests on the same day. The mean score on
the history test is 55.8 and that on the maths test is 53.8.
The score of each student is plotted in the diagram shown below.

A scatte, diagram showint the mathr test scores against history test
scores of a group of students
90
_-t t_
-_+
80
70 ls-J-
.60 -
+ l r1 + --# t-+
Eto #-"]- --1- '-+ ---.{-
E:o -#=.i--
-1--r--l- tta
20 -ti-:]:i]|_]- ---+-
- -+---+- -t I tl
-1-
10
0 -t-----t------l--
0 20 40 60 80 100
History Scores
a) Plot the mean of the distribution and label it as point M.
b) Draw a suitable line of best fit.
c) Describe the relationships between the scores on maths and history tests.

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