Variance of frequency distribution table (numerical variable)
S3 methods for the variance of a fdt
.
Useful to estimate the variance (when the real data vector is not known) from a previous fdt
.
## S3 generic var(x, ...) ## S3 methods: numerical ## Default S3 method: var(x, ...) ## S3 method for class 'fdt' var(x, ...) ## S3 method for class 'fdt.multiple' var(x, ...)
x |
A |
... |
Required to be generic. |
var.fdt
calculates the value of the variance based on a known formula.
var.fdt.multiple
calls var.fdt
for each variable, that is, each column of the data.frame.
var.fdt
returns a numeric vector containing the value of the median of the fdt
.
median.fdt.multiple
returns a list, where each element is a numeric vector
containing the value of the variance of the fdt
for each variable.
José Cláudio Faria
Enio G. Jelihovschi
Ivan B. Allaman
sd.fdt
, mean.fdt
.
mdf <- data.frame(x=rnorm(1e2, 20, 2), y=rnorm(1e2, 30, 3), z=rnorm(1e2, 40, 4)) head(mdf) apply(mdf, 2, var) var(fdt(mdf))
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