pbivgeo {BivGeo} R Documentation

## Joint Cumulative Function for the Basu-Dhar Bivariate Geometric Distribution

### Description

This function computes the joint cumulative function of the Basu-Dhar bivariate geometric distribution assuming arbitrary parameter values.

### Usage

pbivgeo(x, y, theta, lower.tail = TRUE)

### Arguments

 x matrix or vector containing the data. If x is a matrix then it is considered as x the first column and y the second column (y argument need be setted to NULL). Additional columns and y are ignored. y vector containing the data of y. It is used only if x is also a vector. Vectors x and y should be of equal length. theta vector (of length 3) containing values of the parameters \theta_1, \theta_2 and \theta_3 of the Basu-Dhar bivariate Geometric distribution. The parameters are restricted to 0 < \theta_i < 1, i = 1,2 and 0 < \theta_3 \le 1. lower.tail logical; If TRUE (default), probabilities are P(X \le x, Y \le y) otherwise P(X > x, Y > y).

### Details

The joint cumulative function for a random vector (X, Y) following a Basu-Dhar bivariate geometric distribution could be written as:

P(X \le x, Y \le y) = 1 - (\theta_{1}\theta_3)^{x} - (\theta_{2}\theta_3)^{y} + \theta_{1}^{x}\theta_{2}^{y} \theta_{3}^{\max(x,y)}

and the joint survival function is given by:

P(X > x, Y > y) = \theta_{1}^{x}\theta_{2}^{y} \theta_{3}^{\max(x,y)}

### Value

pbivgeo gives the values of the cumulative function.

Invalid arguments will return an error message.

### Author(s)

Ricardo P. Oliveira rpuziol.oliveira@gmail.com

Jorge Alberto Achcar achcar@fmrp.usp.br

### Source

pbivgeo is calculated directly from the definition.

### References

Basu, A. P., & Dhar, S. K. (1995). Bivariate geometric distribution. Journal of Applied Statistical Science, 2, 1, 33-44.

Li, J., & Dhar, S. K. (2013). Modeling with bivariate geometric distributions. Communications in Statistics-Theory and Methods, 42, 2, 252-266.

Achcar, J. A., Davarzani, N., & Souza, R. M. (2016). Basuâ€“Dhar bivariate geometric distribution in the presence of covariates and censored data: a Bayesian approach. Journal of Applied Statistics, 43, 9, 1636-1648.

de Oliveira, R. P., & Achcar, J. A. (2018). Basu-Dhar's bivariate geometric distribution in presence of censored data and covariates: some computational aspects. Electronic Journal of Applied Statistical Analysis, 11, 1, 108-136.

Geometric for the univariate geometric distribution.

### Examples

# If x and y are integer numbers:

pbivgeo(x = 1, y = 2, theta = c(0.2, 0.4, 0.7), lower.tail = TRUE)
# [1] 0.79728

# If x is a matrix:

matr 	<- 	 matrix(c(1,2,3,5), ncol = 2)
pbivgeo(x = matr, y = NULL, theta = c(0.2,0.4,0.7), lower.tail = TRUE)
# [1] 0.8424384 0.9787478

# If lower.tail = FALSE:

pbivgeo(x = 1, y = 2, theta = c(0.2, 0.4, 0.7), lower.tail = FALSE)
# [1] 0.01568

matr 	<- 	 matrix(c(1,2,3,5), ncol = 2)
pbivgeo(x = matr, y = NULL, theta = c(0.9,0.4,0.7), lower.tail = FALSE)
# [1] 0.01975680 0.00139404

[Package BivGeo version 2.0.1 Index]