The table below shows the number of hours per week (X) a student spends studying and the final percentage grade (Y) in M
Posted: Mon May 09, 2022 12:08 pm
The table below shows the number of hours per week (X) a student
spends studying and the final percentage grade (Y) in Maths:
Study hours per week (X) 4 11 12 22 7 13
Percentage grade in Maths (Y) 42 64 72 92 54 84
Also given are the values of the 4 sums
(Sum)x =69; (Sum)y =408; (Sum)x2 =983;
(Sum)y2 =29480:
(a) Calculate the sample means xbar and ybar, and the sum of
the products (Sum)xy.
(b) Calculate the correlation coefficient, r , rounded to 2 decimal
places and then state the nature of the correlation. (5
marks)
(c) Find the equation of the regression line y = a + bx , and use
it to estimate the percentage Maths grade for a student who spends
24 hours a week studying.
(d) Comment on the estimate found in part 2(c).
spends studying and the final percentage grade (Y) in Maths:
Study hours per week (X) 4 11 12 22 7 13
Percentage grade in Maths (Y) 42 64 72 92 54 84
Also given are the values of the 4 sums
(Sum)x =69; (Sum)y =408; (Sum)x2 =983;
(Sum)y2 =29480:
(a) Calculate the sample means xbar and ybar, and the sum of
the products (Sum)xy.
(b) Calculate the correlation coefficient, r , rounded to 2 decimal
places and then state the nature of the correlation. (5
marks)
(c) Find the equation of the regression line y = a + bx , and use
it to estimate the percentage Maths grade for a student who spends
24 hours a week studying.
(d) Comment on the estimate found in part 2(c).