Numbers of frogs on lakes as determined by call and visual methods.

Description

Hypothetical population of numbers of frogs on lakes as determined by call and visual methods.

Format

A data frame with 1000 observations on the following 2 variables:

call

Abundance determined from the ‘call’ method.

visual

Abundance determined from the ‘visual’ method.

Note

Data were randomly determined using the following code:

library(MASS) round(mvrnorm(n=1000,c(120,225),matrix(c(25,18,18,35),2,2),empirical=TRUE),0)

Source

Randomly determined from realistic values provided by the Sigurd Olson Environmental Institute, Northland College, Ashland, WI.