R_package_hallmark: R Package for project 3

#' ggplot(crabs, aes(x = carapace_length, y = body_depth)) + 
#'  geom_point(size = 0.5) +        ## making the points small to help see the regression line
#'  geom_smooth(method = "lm",     ## make a trendline using "lm"
#'              color = "navy",    ## make the trendline navy
#'              size = 0.5,        ## make the line small to help see the confidence interval for TUTORIAL REASONS
#'              fill = "deeppink4") + ## fill for the confidence interval
#'  labs(x = "Carapace length (mm)", 
#'       y = "Body depth (mm)", 
#'       title = "Linear regression to predict crab body depth") + 
#'  annotate("text",                ## geom to annotate with is text annotation
#'           x = 20, y = 30,         ## coordinates of the label, decided after trying several places..
#'           label = "R^2 == 0.966", ## label itself, double equals is needed for use with parse=T
#'           parse=T,               ## makes label actually show as a formula, with squared as superscript!
#'           color = "firebrick", size = 5)  + ## font color and size 
#'  theme_bw()