wgmean {climwin}

Calculate within group means.

Description

Calculate group means of a variable. Used to test for 'between individual effects'. See methods outlined in van de Pol and Wright 2009 for more detail.

Usage

wgmean(covar, groupvar)

Arguments

covar

Continuous variable for which group means will be calculated. Please specify the dataset in which the variable is found (i.e. data$var).

groupvar

Grouping variable within which means will be calculated. For example, individual ID or site/plot ID. Please specify the dataset in which the variable is found (i.e. data$var).

Value

Returns a vector containing numeric values. This can be used to differentiate within and between group effects in a model. See function wgdev to calculate within group deviance. See van de Pol and Wright 2009 for more details on the method.

Author(s)

Martijn van de Pol and Jonathan Wright

Examples

# Calculate mean temperature within years from the MassClimate dataset.  

data(MassClimate)

#Calculate year column
library(lubridate)
MassClimate$Year <- year(as.Date(MassClimate$Date, format = "%d/%m/%Y"))

#Calculate mean temperature within each year
within_yr_mean <- wgmean(MassClimate$Temp, MassClimate$Year)

#Add this variable to the original dataset
MassClimate$Within_yr_mean <- within_yr_mean