#' iscam_addtnorm Function
#'
#' This function creates a histogram of the inputted variable and overlays a t density function with df degrees of freedom
#' and a normal density function.
#' @param x a vector of numeric values.
#' @param df degrees of freedom
#' @keywords t
#' @export
#' @import graphics ggplot2
#' @examples
#' data("mtcars")
#' iscam_addtnorm(mtcars$wt, 3)
iscam_addtnorm <- function(x, df){
data <- data.frame(x) # Converting inputted variable into a data frame
ggplot(data, aes(x)) +
geom_histogram( # Histogram of inputted variable
aes_string(y = ("..density..")),
binwidth = (max(x) - min(x)) / 20,
colour = "black",
fill = "white"
) +
stat_function( # t Density curve
geom = "line",
fun = dt,
args = list(df = df),
aes(colour = "t")
) +
stat_function( # Normal density curve
geom = "line",
fun = dnorm,
args = list(mean = mean(x), sd = sd(x)),
aes(colour = "Normal")
) +
labs(y = "Density", x = deparse(substitute(x))) +
# Editing legend
scale_colour_manual("Distribution", values = c("red", "green"))
}
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