Weighted mean, variance and standard deviation calculations

Description

wt.mean calculates the mean given a weighting of the values.

wt.var is the unbiased variance of the weighted mean calculation using equations of GNU Scentific Library (http://www.gnu.org/software/gsl/manual/html_node/Weighted-Samples.htmland.

wt.sd is the standard deviation of the weighted mean calculated as the sqrt of wt.var.

Note: NA data is automatically ommitted from analysis.

Usage

wt.mean(x, wt)

wt.var(x, wt)

wt.sd(x, wt)

Arguments

Value

returns a single value from analysis requested.

Author(s)

Jeremy VanDerWal jjvanderwal@gmail.com

Examples

#define simple data
x = 1:25 # set of numbers
wt = runif(25) #some arbitrary weights

#display means & variances (unweighted and then weighted)
mean(x); wt.mean(x,wt)
var(x); wt.var(x,wt)
sd(x); wt.sd(x,wt)

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(SDMTools)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/SDMTools/wt.mean.Rd_%03d_medium.png", width=480, height=480)
> ### Name: wt.mean
> ### Title: Weighted mean, variance and standard deviation calculations
> ### Aliases: wt.mean wt.sd wt.var
> 
> ### ** Examples
> 
> #define simple data
> x = 1:25 # set of numbers
> wt = runif(25) #some arbitrary weights
> 
> #display means & variances (unweighted and then weighted)
> mean(x); wt.mean(x,wt)
[1] 13
[1] 12.8334
> var(x); wt.var(x,wt)
[1] 54.16667
[1] 51.78277
> sd(x); wt.sd(x,wt)
[1] 7.359801
[1] 7.196025
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>