mean.fdt {fdth}

Mean of frequency distribution table (numerical variable)

Description

S3 method for the arithmetic mean of a fdt.
Useful to estimate the arithmetic mean (when the real data vector is not known) from a previous fdt.

Usage

## S3 method: numerical 
## S3 method for class 'fdt'
mean(x, ...)

Arguments

x

a fdt (simple or multiple) object.

...

required by generic.

Details

mean.fdt calculates the mean value based on a known formula using the midpoint of each interval class. mean.fdt.multiple calls mean.fdt for each variable, that is, each column of the data.frame.

Value

mean.fdt returns a numeric vector containing the mean value of the fdt. mean.fdt.multiple returns a list, where each element is a numeric vector containing the mean value of the fdt for each variable.

Author(s)

Faria, J. C.
Allaman, I. B
Jelihovschi, E. G.

See Also

median.fdt, mfv.

Examples

mdf <- data.frame(x=rnorm(1e3, 
                          20, 
                          2),
                  y=rnorm(1e3, 
                          30,
                          3),
                  z=rnorm(1e3,
                          40,
                          4))

head(mdf)

apply(mdf,
      2,
      mean)

mean(fdt(mdf))