Significant at 1% probability level Table 5: F-test of homoscedasticity
In determining the importance of country of origin attribute vis a vis other attributes, mean responses for each product attribute were compared, and although this data was interval, assumptions of normality and homoscedasticity
were not met so normality was assessed using measures of central tendency and Kolmogorov-Smirnov tests.
When the assumptions of normality and homoscedasticity
are tested in sections 4 and 5, they are sometimes satisfied and at other times violated.
Hence, the residuals report no serial correlation, conditional homoscedasticity
and no data dependence.
The method of IV requires covariance homoscedasticity
assumption A3, and A3 is artificial in many choice theoretic economic models of schooling.
We test the homoscedasticity
of the two regressions using the statistic proposed by Harvey (1974).
This suggests there is not a minimum number of years of simulation required to diminish prediction error; (2) Problems of lack of homoscedasticity
were observed, the largest errors associated to the largest rainfall events.
Standard statistical texts such as Blalock's Social Statistics set out these assumptions explicitly: interval level data, normal distributions (including bi- and multi-variate normality), and homoscedasticity
(variances of the Y distributions are the same for each value of X) (Blalock 1960, 276).
An evaluation of assumptions yielded no gross violations of assumptions of normality, linearity, and homoscedasticity
When the classical least squares assumptions are not met, particularly with regard to the normality and homoscedasticity
(equal variance) assumption, several transformations were well known long before the work of Box and Cox .
2~): Test for Heteroscedasticity Errors: This test statistic is based on White (1980), and the null hypothesis asserts unconditional homoscedasticity
Quandt, "Some Tests for Homoscedasticity
," Journal of the American Statistical Association (1965): 539-547.