In a multiple regression equation, two independent variables are considered, and
ID: 3243551 • Letter: I
Question
In a multiple regression equation, two independent variables are considered, and the sample size is 27. The regression coefficients and the standard errors are as follows.
Conduct a test of hypothesis to determine whether either independent variable has a coefficient equal to zero. Would you consider deleting either variable from the regression equation? Use the .05 significance level. (Round your answers to 3 decimal places. Negative amounts should be indicated by a minus sign.)
rev: 03_18_2016_QC_CS-46019
b1 = 1.027 Sb1 = 0.58 b2 = -2.529 Sb2 = 0.7Explanation / Answer
For the first hypthesis -
H0: 1 = 0
H1: 1 0
Sample size , n = 27
Number of independent variable including intercept = 3
Degree of freedom for the test statistic = 27 - 3 = 24
For two tail test, significance level = 0.05/2 = 0.025
Rejection region for significance level = 0.025 and degree of freedom is given as,
t < -2.064 or t > 2.064
t for b1 coefficient = coeff/Std error = 1.027/0.58 = 1.771
As, t does not lie in the rejection region, we accept the null hypothesis and conclude that 1 = 0 and first independent variable can be deleted from the model.
For the second hypthesis -
H0: 2 = 0
H1: 2 0
Sample size , n = 27
Number of independent variable including intercept = 3
Degree of freedom for the test statistic = 27 - 3 = 24
For two tail test, significance level = 0.05/2 = 0.025
Rejection region for significance level = 0.025 and degree of freedom is given as,
t < -2.064 or t > 2.064
t for b2 coefficient = coeff/Std error = -2.529/0.7 = -3.613
As, t does lie in the rejection region, we reject the null hypothesis and conclude that 2 0 and second independent variable cannot be deleted from the model.
So, The first variable can be deleted, and
The second variable cannot be deleted.
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