The table shows the examination marks of 8 students in Algebra and Statistics tests.
| Algebra (x) |
10 |
24 |
30 |
35 |
48 |
59 |
68 |
70 |
Statistics (y) |
30 |
47 |
44 |
71 |
60 |
89 |
97 |
74 |
(a) Draw a scatter diagram for the data.
(b) Find x, the mean of x; and y, the mean of y and plot (x, y) on the graph.
(c) Draw a line of best fit to pass through (x, y).
(d) From your graph:
- find the equation of the line;
- estimate the statistics marks for a student who scored 50 in Algebra
In this question, candidates were expected to plot the values of y against the respective values of x, calculate the means x of the x values and y of the y values respectively and draw the line of best fit to pass through the point (x, y) then from the graph, answer sub questions (i) and (ii). Some candidates made the mistake of interchanging the axes and this cost them some marks.