pois.stat: The Poisson Scan Statistic

In SNscan: Scan Statistics in Social Networks

Description

The Poisson scan statistic evaluates the statistic which compares the node attribute within the subgraph with that outside the subgraph while the node attribute follows the Poisson distribution.

Usage

pois.stat(obs, pop, zloc)

Arguments

obs	Numeric vector of observation values.
pop	Numeric vector of population values.
zloc	Numeric vector of selected nodes.

Details

A network with interested attributes is denoted as G=(V,E,X), where X=(x_1,…,x_{|V|}) follows a defined distribution. Suppose a subgraph, Z, is selected.

λ_A(Z)=n_z \ln\big(\frac{p_{11}}{p_0}\big)+(n_G-n_z) \ln\big(\frac{p_{10}}{p_0}\big),

where the estimated parameters are equivalent to those in the binomial distribution.

Value

Three values will be returned. The first value is test statistic. The second is the estimated means which estimated outside the selected nodes. The third is estimated means estimated within the selected nodes.

Author(s)

Taichi Wang <[e-mail]>

References

Kulldorff, M. (1997). A spatial scan statistic. Communications in Statistics-Theory and methods, 26(6), 1481–1496.

See Also

binom.stat

Examples

pois.stat(obs=rpois(n=100, lambda=10),pop=rep(1,100),zloc=1:5)

SNscan documentation built on May 2, 2019, 8:26 a.m.