Amended the typo in R code for Regression through origin

[Eotoke]

Hi, There seems to be a typo in the R code for Regression through the origin. The first column of freqData should be parent instead of child based on this line "freqData <- as.data.frame(table(x, y))" hence the following line should be "names(freqData) <- c("parent", "child", "freq")" instead of the original "names(freqData) <- c("child", "parent", "freq")"

For your review please. Thanks :)