The test statistic is t = b / std error of b = 5.29 / 1.615 = 3.2755.
Critical t-values are ± 2.101 for the degrees of freedom = n ? k ? 1 = 18 for alpha = 0.05. For alpha = 0.01, critical t-values are ± 2.878. At both levels (two-tailed tests) we can reject H0 that b = 0.
Heteroskedasticity occurs when the variance of the residuals is not the same across all observations in the sample. Autocorrelation refers to dependent error terms. Nonstationarity is when the regression changes over time.
5、A study of a sample of incomes (in thousands of dollars) of 35 individuals shows that income is related to age and years of education. The following table shows the regression results:
Coefficient
Standard Error
t-statistic
P-value
Intercept
5.65
1.27
4.44
0.01
Age
0.53
?
1.33
0.21
Years of Education
2.32
0.41
?
0.01
Anova
df
SS
MS
F
Regression
?
215.10
?
?
Error
?
115.10
?
Total
?
?
The standard error for the coefficient of age and t-statistic for years of education are: