# 420Pr1 - Practice Problem 1 Alex obtains a random sample of...

This preview shows pages 1–2. Sign up to view the full content.

Practice Problem 1. Alex obtains a random sample of seven students from STAT 100 class he taught in Fall Semester of 2006 and wants to use it to see if there is a relationship between the number of absences and students’ final grade. The data and the scatterplot are given below. Number of Absences, x Final Grade Percentage, y 6 70 2 92 15 47 9 72 11 49 5 96 8 78 Consider the model Y i = β 0 + β 1 x i + ε i , where ε i ’s are i.i.d. N ( 0, σ 2 ). a) Find the equation of the least-squares regression line. Add the regression line to the scatter plot. b) Use the equation of the least-squares regression line obtained in part (a) to predict the final grade percentage for a student who missed 20 classes. c) Use the equation of the least-squares regression line obtained in part (a) to predict the final grade percentage for a student who missed 7 classes. d) In which prediction ( part (b) or part (c) ) would we have more confidence? Why? e) Use the equation of the least-squares regression line obtained in part (a) to find the residuals. f)*

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 6

420Pr1 - Practice Problem 1 Alex obtains a random sample of...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online