characRV: Characteristics of Random Variables.

In RcmdrPlugin.TeachStat: R Commander Plugin for Teaching Statistical Methods

Characteristics of Random Variables.

Description

This function computes the main characteristics of a random variable (expectation, median, standard deviation, ...)

Usage

characRV(D, charact = c("expectation", "median", "sd", "IQR", "skewness", "kurtosis", 
         "moment", "cmoment"), moment = 1, cmoment = 2)

Arguments

D	An object of the class Distribution.
charact	any of "expectation", "median", "sd", "IQR", "skewness", "kurtosis", "moment", "cmoment"
moment	an integer indicating the moment with respect to the origin to be calculated.
cmoment	an integer indicating the moment with respect to the expectation to be calculated.

Value

'characRV' returns a table containing the selected characteristics.

See Also

E, median, sd, IQR, skewness, kurtosis

Examples

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (D, charact = c("expectation", "median", "sd", "IQR", 
    "skewness", "kurtosis", "moment", "cmoment"), moment = 1, 
    cmoment = 2) 
{
    if (missing(charact)) 
        charact <- c("expectation", "sd")
    charact <- match.arg(charact, c("expectation", "median", 
        "sd", "IQR", "skewness", "kurtosis", "moment", "cmoment"), 
        several.ok = TRUE)
    moment <- if ("moment" %in% charact) 
        moment
    else NULL
    cmoment <- if ("cmoment" %in% charact) 
        cmoment
    else NULL
    mom <- if (!is.null(moment)) 
        paste("alpha_", moment, sep = "")
    else NULL
    cmom <- if (!is.null(cmoment)) 
        paste("mu_", cmoment, sep = "")
    else NULL
    chars <- c(c("expectation", "median", "sd", "IQR", "skewness", 
        "kurtosis")[c("expectation", "median", "sd", "IQR", "skewness", 
        "kurtosis") %in% charact], mom, cmom)
    nchars <- length(chars)
    table <- matrix(0, 1, nchars)
    rownames(table) <- gsub("[[:space:]]", "", deparse(substitute(D)))
    colnames(table) <- chars
    if ("expectation" %in% chars) 
        table[, "expectation"] <- distrEx::E(D)
    if ("median" %in% chars) 
        table[, "median"] <- distrEx::median(D)
    if ("sd" %in% chars) 
        table[, "sd"] <- distrEx::sd(D)
    if ("IQR" %in% chars) 
        table[, "IQR"] <- distrEx::IQR(D)
    if ("skewness" %in% chars) 
        table[, "skewness"] <- distrEx::skewness(D)
    if ("kurtosis" %in% chars) 
        table[, "kurtosis"] <- distrEx::kurtosis(D)
    if ("moment" %in% charact) 
        table[, mom] <- distrEx::E(D, fun = function(x) {
            x^moment
        })
    if ("cmoment" %in% charact) 
        table[, cmom] <- distrEx::E(D, fun = function(x) {
            (x - distrEx::E(D))^cmoment
        })
    print(table)
    return(invisible(table))
  }

RcmdrPlugin.TeachStat documentation built on Nov. 14, 2023, 5:08 p.m.