Question
Six students revise for a test.
The scatter diagram shows the time, in hours, each student spent revising and their mark in the test.
(a) The data for two more students is shown in the table.
Plot these two points on the scatter diagram.
(b) What type of correlation is shown on the scatter diagram?
(c) Draw a line of best fit on the scatter diagram.
(d) Another student spent 5.5 hours revising.
Estimate a mark for this student.
Answer/Explanation
Ans:
(a) Points plotted at (4.5, 33) and (6.5, 35)
(b) Positive
(c) Correct ruled line
(d) 33.5 to 37.5
Question
Aisha records the distance she runs and her average speed.
The results are shown in the scatter diagram.
(a) The table shows the results of four more runs.
On the scatter diagram, plot these points.
(b) What type of correlation is shown in the scatter diagram?
………………………………………….
(c) On the scatter diagram, draw a line of best fit.
(d) Use your line of best fit to estimate her average speed when she runs a distance of 6km.
…………………………………. km/h
Answer/Explanation
(a) 4 points correctly plotted
(b) Negative
(c) Correct ruled line of best fit
(d) 10 to 12
Question
The scatter diagram shows the marks obtained in a Mathematics test and the marks obtained in an
English test by 15 students.
(a) Describe the correlation.
(b) The mean for the Mathematics test is 47.3 .
The mean for the English test is 30.3 .
Plot the mean point (47.3, 30.3) on the scatter diagram above.
(c) (i) Draw the line of best fit on the diagram above.
(ii) One student missed the English test.
She received 45 marks in the Mathematics test.
Use your line to estimate the mark she might have gained in the English test.
Answer/Explanation
(a) Negative correlation