linear modeling

# drawing a scatter plot and regression line

# draw a scatter plot
library(LSD)
heatscatter( dta$a, dta$b, cor = TRUE, method = "pearson" )

# add regression line
abline( lm( dta$b ~ dta$a ) )              # switch columns (a<-->b)

# FYI of linear modeling
lmodel <- lm( dta$b ~ dta$a )              # linear modeling
summary( lmodel )                          # just looking at the results
coef( lmodel )                                 
intcp <- coef(lmodel)[1]                   # extract intercept value
slp <-  coef(lmodel)[2]                    # extract slope value 
abline(intcp, slp)                         # draw regression line using slope and intercept values