8. In this problem we develop the rudiments of the theory of linear regression. Suppose that associated with an experiment there are two random variables y and x. If the outcomes of severa] measurements of y and x are plotted on a two-dimensional graph, the result may look somewhat like that shown in Figure 4.6. These results could be effectively summarized by saying that y is approximately a linear func- tion of x. So y would be described by the equation y = a + bx which LEAST-SQUARES ESTIMATION is represented by the dashed line in the figure. A natural way to choose the appropriate dashed line is to choose that line which minimizes the total sum of the squared errors E, e;? where e, = y, – (a + bx) is the vertical distance between an observation point on the graph and the dashed line. Figure 4.6 Regression

Linear Algebra: A Modern Introduction
4th Edition
ISBN:9781285463247
Author:David Poole
Publisher:David Poole
Chapter2: Systems Of Linear Equations
Section2.4: Applications
Problem 2EQ: 2. Suppose that in Example 2.27, 400 units of food A, 500 units of B, and 600 units of C are placed...
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8. In this problem we develop the rudiments of the theory of linear
regression. Suppose that associated with an experiment there are two
random variables y and x. If the outcomes of severaļ measurements of
y and x are plotted on a two-dimensional graph, the result may look
somewhat like that shown in Figure 4.6. These results could be
effectively summarized by saying that y is approximately a linear func-
tion of x. So y would be described by the equation y = a + bx which
LEAST-SQUARES ESTIMATION.
is represented by the dashed line in the figure. A natural way to choose
the appropriate dashed line is to choose that line which minimizes
the total sum of the squared errors E, e;? where e, = y, - (a + bx;)
is the vertical distance between an observation point on the graph and
the dashed line.
Figure 4.6 Regression
(a) Show that the best linear approximation is given by
y = ỹ + b(x- x)
where
E* b=
y =
(b) Show that b may be alternatively expressed as
E(v - )(x – X)
N
Transcribed Image Text:8. In this problem we develop the rudiments of the theory of linear regression. Suppose that associated with an experiment there are two random variables y and x. If the outcomes of severaļ measurements of y and x are plotted on a two-dimensional graph, the result may look somewhat like that shown in Figure 4.6. These results could be effectively summarized by saying that y is approximately a linear func- tion of x. So y would be described by the equation y = a + bx which LEAST-SQUARES ESTIMATION. is represented by the dashed line in the figure. A natural way to choose the appropriate dashed line is to choose that line which minimizes the total sum of the squared errors E, e;? where e, = y, - (a + bx;) is the vertical distance between an observation point on the graph and the dashed line. Figure 4.6 Regression (a) Show that the best linear approximation is given by y = ỹ + b(x- x) where E* b= y = (b) Show that b may be alternatively expressed as E(v - )(x – X) N
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