Can these residuals be regarded heteroscadastic?
I have tested the residuals are normally distributed.
The number of data points in your residual plot is a bit small to know for sure, but I see nothing there that strongly suggests heteroscedasticity. The warning flag for a violation of homoscedasticity would typically be a "funnel-shaped" scatter of points in the plot -- short/narrow vertical bands of data points on one side of the plot (either the left or right side), getting taller/wider as you move toward the other side. Your plot seems to show a fairly random scatter, with no pronounced funnel pattern, at least not in the few data points you have. BTW -- the non-significant departure from normality you apparently got is in part due to the small sample size. But, based on the residual plot above, I tend to agree that non-normality is probably not a concern in these data. I would worry more about the sample size. If your regression includes more than 2 predictor variables, the results from such a small sample would be suspect.
The number of data points in your residual plot is a bit small to know for sure, but I see nothing there that strongly suggests heteroscedasticity. The warning flag for a violation of homoscedasticity would typically be a "funnel-shaped" scatter of points in the plot -- short/narrow vertical bands of data points on one side of the plot (either the left or right side), getting taller/wider as you move toward the other side. Your plot seems to show a fairly random scatter, with no pronounced funnel pattern, at least not in the few data points you have. BTW -- the non-significant departure from normality you apparently got is in part due to the small sample size. But, based on the residual plot above, I tend to agree that non-normality is probably not a concern in these data. I would worry more about the sample size. If your regression includes more than 2 predictor variables, the results from such a small sample would be suspect.
While I agree with what Burke said I would notice that the spread changes in different areas of the plot. Hence l might run this data through a Box-Cox routine just to see if a transformation was recommended. Better safe than sorry I guess. David Booth
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