search for: scireg3

Hi all, In using the identify command, I get the following message > plot(hatvalues(scireg3)) > abline(h=.0154,lty=2) # plots a reference line at (k + 1)/n > identify(1:1165, hatvalues(scireg3),row.names(sciach)) Error in xy.coords(x, y) : 'x' and 'y' lengths differ which doesn't allow me to see the observation number when I scroll over with the mouse. Wh...

Hi all, I'm running White's test to correct for non-constant error variance and I am using the Anova function in the package CAR. My command structure is > Anova(scireg3, white.adjust="hc3") where scireg3 is an object from lm. I get the message "Error in SS[i] <- SS.term(names[i]) : nothing to replace with" What does this mean and how do I fix it. Thanks in advance. David -- =========================================================...

Hi all, It seems that I can get White's (HC3) test using MASS. The syntax I used for the particular problem is anova(scireg3, white.adjust="hc3") where scireg3 is an object from the lm function. But, the anova summary table is all I get. I don't get the new estimates or standard errors correcting for heteroskedasticity. Is there a way to get that information? Thanks in advance, David -- =========...

Let me try to be more specific. The x y coordinates are different because of NAs in the dataset. In this analysis, a set of hat values (a measure of influence in regression) is given for each observation. On the basis of the regression that was run to get these hat values, the sample size was 1164 (one removed due to NA). The length of the data set is 1165. If I remove the NA from the