Question

The following data gives the number of hours 10 students spent studying and their corresponding grades on their midterm exams.

Hours Spent Studying	0.5	1	1.5	2	2.5	3	4	4.5	5	5.5
Midterm Grades	63	66	69	72	75	78	81	87	93	96

Calculate the correlation coefficient, r. Round your answer to three decimal places.

Answer 1

	x	y	(x-xbar)^2	(y-ybar)^2	(x-xbar)*(y-ybar)
	0.5	63	6.0025	225	36.75
	1	66	3.8025	144	23.4
	1.5	69	2.1025	81	13.05
	2	72	0.9025	36	5.7
	2.5	75	0.2025	9	1.35
	3	78	0.0025	0	0
	4	81	1.1025	9	3.15
	4.5	87	2.4025	81	13.95
	5	93	4.2025	225	30.75
	5.5	96	6.5025	324	45.9
sum	29.5	780	27.225	1134	174
mean	2.95	78	sxx	syy	sxy

r= correlation coefficient,

r=sxy/sqrt(sxx*syy)

r=174/sqrt(27.225*1134)

r=0.99028

#correlation coefficient,=0.990