Question

2) The two scatterplots below show the relationship between final and mid-semester exam grades recorded during several years for a Statistics course at a university (a) Based on these graphs, which of the two exams has the strongest correlation with the final exam grade? Explain. (b) Can you think of a reason why the correlation between the exam you chose in part (a) and the final exam is higher? 100 100 80- 80 Final Exam 60 5 40 40 100 60 40 60 40 30 100 Exam 2 Exam 1 Solution for (a): Solution for (b):

Answer 1

2

Solution for (A) THERE ARE TWO SCATTERPLOT DIAGRAM, IN WHICH FIG . 1 SHOWS DATA POINTS THAT ARE SCATTERED FAR FROM THE LINE OF BEST FIT AND THE FIG. 2 THAT HAS DATA POINTS CONCENTRATED NEAR THE LINE OF BEST FIT.

So, the data points that are concentrated near the line of best are considered to be showing the strongest correlation with the final year exams.

1004 160 Final Exam 100 1401 40 00 100 Ecam2

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Solution for (b): When the data points are near to each other the variability in the data is expected least. So we can assume the strongest relation between them. Since in the fig. 2 data points are concentrated very near to each other So, there variability is less and the correlation is strongest.

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