1. In an effort to demonstrate the inmportance of class attendance, a statistics instructor takes daily attendance oe semester throughout a Stat 289 class. A random sample of the students is selected. Their number of absences and corresponding final grades are listed in the following table: Student Student Student Student Student Student 1 3 4 6. Absences 0. 2 1 4 5 9. X Grade 85 93 70 51 42 50 y Part of a linear regression analysis has been completed with the following sums already calculated: Ey = 391, Ey? = 27639, Ery = 1120. Ex = 21. Ex2 = 127. (a) Calculate the numbers s, Sy, Sxy, and the correlation coefficient r for this data. (b) Find the equation y = a+ bx of the linear regression (best fit) line. (Show the calculation.) (c) What is the predicted grade for a student who is absent 4 times in the semester?

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1. In an effort to demostrate the importance of class attendance, a statistics instructor
takes daily attendance one semester throughout a Stat 289 class. A random sample
of the students is selected. Their number of absences and corresponding final grades
are listed in the following table:
Student
Student
Student
Student
Student
Student
1
3
4
6.
Ex
Absences
0.
2
1
4
6.
Grade
85
93
70
51
42
50
y
Part of a linear regression analysis has been completed with the following sums already
calculated:
Σα21.
= 127, Ey = 391, Ey² = 27639,
Ery = 1120.
(a) Calculate the numbers s, 8y, Sy, and the correlation coefficient r for this data.
(b) Find the equation y = a + bx of the linear regression (best fit) line. (Show the
calculation.)
(c) What is the predicted grade for a student who is absent 4 times in the semester?
Transcribed Image Text:1. In an effort to demostrate the importance of class attendance, a statistics instructor takes daily attendance one semester throughout a Stat 289 class. A random sample of the students is selected. Their number of absences and corresponding final grades are listed in the following table: Student Student Student Student Student Student 1 3 4 6. Ex Absences 0. 2 1 4 6. Grade 85 93 70 51 42 50 y Part of a linear regression analysis has been completed with the following sums already calculated: Σα21. = 127, Ey = 391, Ey² = 27639, Ery = 1120. (a) Calculate the numbers s, 8y, Sy, and the correlation coefficient r for this data. (b) Find the equation y = a + bx of the linear regression (best fit) line. (Show the calculation.) (c) What is the predicted grade for a student who is absent 4 times in the semester?
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