Question

Consider the accompanying set of dependent and independent variables. The variable x3 is qualitative with H=​High, M=​Medium, and L=Low. Complete parts a and b below.

y 63 53 77 53 38 43 34 20 13
x1 45 42 40 37 27 24 20 14 12
x2 74 62 80 53 42 48 35 16 13
x3 H H L M H M L L M


Required:
a. Using​ technology, construct a regression model using all three independent variables.​
b. Complete the regression equation for the model​ below, where x3 represents the dummy variable Cond1​, and x4 represents the dummy variable Cond2.

y= ____ + (____)x2+ (____)x3 + (____)x4

Answer 1

Y = 6.6406 + 0.2068x2 + 0.7995x3 - 3.607x4

Explanation:

y 63 53 77 53 38 43 34 20 13

x1 45 42 40 37 27 24 20 14 12

x2 74 62 80 53 42 48 35 16 13

x3 H H L M H M L L M

For regression analysis : all variables must be quantitative ;

X3 variable may be represented as thus;

L = 1 ; M = 2 ; H = 3

Hence ;

X3 = 3 3 1 2 1 2 1 1 2

y= ____ + (____)x2+ (____)x3 + (____)x4

Using the online multiple regression calculator :

Y = 6.6406 + 0.2068x2 + 0.7995x3 - 3.607x4

From the general formular of a linear model:

y = w1x1 + w2x2 +... + wnxn + c = 0

Where c = intercept

w1,.. wn = weight of explanatory variable

Hence, the weights of x2 = 0.2068

Weight of x3 = 0.7995

Weight of x4 = - 3.607

Intercept = 6.6406