Could someone explain to me what is criterion for interpretation of Breusch-Pagan test?
I have applied ncvTest test from the package car in R on a simple linear regression with one predictor variable e.g. lm(weight~size). I have the following result:
Chisquare = 7.182687 Df = 1 p = 0.007361039
I see in other questions that p = 0.073459 implies heteroscedasticity
while p = 0.6283239 and p-value = 0.858 imply homoscedascity. By looking at these samples I would assume that my result set is heteroscedasticit, but I would like to know is p value only criterion and is there some boundary value for yes/no decision (i.e. some p value between 0.007 and 0.6).
Does Chisquare value matters?
Best Answer
The Breush-Pagan test creates a statistic that is chi-squared distributed and for your data that statistic=7.18. The p-value is the result of the chi-squared test and (normally) the null hypothesis is rejected for p-value < 0.05. In this case, the null hypothesis is of homoskedasticity and it would be rejected.