R: One-truncated Zeta Distribution Family Function

otzeta {VGAM} | R Documentation

## One-truncated Zeta Distribution Family Function

### Description

Estimates the parameter of the 1-truncated zeta distribution.

### Usage

    otzeta(lshape = "loglink", ishape = NULL, gshape = exp((-4:3)/4), zero = NULL)

### Arguments

`lshape, ishape, gshape, zero` | Same as `zetaff`.

### Details

The 1-truncated zeta distribution is the ordinary zeta distribution but with the probability of one being 0. Thus the other probabilities are scaled up (i.e., divided by 1-P[Y=1]). The mean is returned by default as the fitted values. More details can be found at `zetaff`. Multiple responses are handled.

### Value

An object of class `"vglmff"` (see `vglmff-class`). The object is used by modelling functions such as `vglm`, and `vgam`.

### Author(s)

T. W. Yee

### See Also

`Otzeta`, `zetaff`, `oizeta`, `diffzeta`, `zeta`, `dzeta`, `hzeta`, `zipf`.

### Examples

    odata <- data.frame(x2 = runif(nn <- 1000))  # Artificial data
    odata <- transform(odata, shape = loglink(-0.25 + x2, inverse = TRUE))
    odata <- transform(odata, y1 = rotzeta(nn, shape))
    with(odata, table(y1))
    ofit <- vglm(y1 ~ x2, otzeta, data = odata, trace = TRUE, crit = "coef")
    coef(ofit, matrix = TRUE)

[Package VGAM version 1.1-3 Index]