HW1
Date: 08/29/2009
MTHSC 805
Data Analysis
Fall 2009
Abhishek Pandey
1.
Problem 1.3
The objection made by participant is not valid because hardness of items molded
from plastic
Y
does not only depends on natural chemical processes but there can
be other external factors also which affects it. For example,temperature in which
it is kept and it may not be possible to take into account of all the factors affecting
its hardness. So I think regression analysis is appropriate for the sitiuation.
2.
Problem 1.5
I do not agree with the student,since a simple regression model is given by
Y
i
=
β
0
+
β
1
Xi
+
±
i
where error term
±
i
is random with mean
E
[
±
i
] = 0
So it should be
E
(
Y
i
) =
E
[
β
0
+
β
1
X
i
+
±
i
] =
β
0
+
β
1
X
i
+
E
[
±
i
] =
β
0
+
β
1
X
i
(1)
3.
Problem 1.13
(a) Data used were observational,since there was no control over the study.
(b) A positive relation between participants productivity level and amount of
time spent in class participation may not imply that productivity is direct
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.
 Fall '09
 Dr.F.Vera
 Statistics, Linear Regression, Regression Analysis, Yi, Errors and residuals in statistics, Xi Yi − Xi Yi

Click to edit the document details