Question

Question 13

1. Use this problem for #13-16.

   Dr. Armstrong thinks that a student's final grade is related to his/her number of absences. She took a sample of 9 students and found their number of absences and their final grades.

   Number of absences x	0	1	2	2	3	3	4	5	6
   Final grade y	96	91	78	83	75	62	70	68	56

   The correlation coefficient is .912.

   True

   False

Question 14

1. The equation for the regression line is y = -6.28x + 93.6.

   True

   False

Question 15

1. Dr. Armstrong can predict that the final grade for a student who has 8 absences is:

   		144
   		43
   		37
   		65

Answer 1

X	y	XY	X^2	Y^2
0	96	0	0	9216
1	91	91	1	8281
2	78	156	4	6084
2	83	166	4	6889
3	75	225	9	5625
3	62	186	9	3844
4	70	280	16	4900
5	68	340	25	4624
6	56	336	36	3136

From the above table and formula we get the value are as;

n	9
sum(XY)	1780.00
sum(X)	26.00
sum(Y)	679.00
sum(X^2)	104.00
sum(Y^2)	52599.00
Numerator	-1634.00
Denominator	1791.93
r	-0.912

The correlation coefficient is -0.912

false

14)

From the above table and formula we get the value are as :

n	9
sum(XY)	1780.00
sum(X)	26.00
sum(Y)	679.00
sum(X^2)	104.00
sum(Y^2)	52599.00

b	-6.2846
a	93.6000

ycap =a + bx

yacp = 93.6 - 6.28x

true

15)

when x = 8

Prdicted value = 93.6 - 6.28 * 8

Predicted value = 43