# seqivardur: Variance of spell durations in individual sequences In TraMineR: Trajectory Miner: a Sequence Analysis Toolkit

 seqivardur R Documentation

## Variance of spell durations in individual sequences

### Description

Variance of spell durations of individual state sequences.

### Usage

``````seqivardur(seqdata, type=1, with.missing=FALSE)

## S3 method for class 'seqivardur'
print(x, stat='var', ...)
``````

### Arguments

 `seqdata` a state sequence object (`stslist`) as returned by `seqdef`. `type` either 1 or 2. The default `type=1` ignores non visited states. Type 2 takes into account the 0-time spent in non-visited states (see Details). `with.missing` logical: should non-void missing values be treated as a regular state? If `FALSE` (default) missing values are ignored. `x` an outcome of `seqivardur`. `stat` string or vector of strings. Duration statistic to be printed. Either `'mean'` (mean duration), `'std'` (standard deviation), `'var'` (variance), `'vmax'` (maximum variance for number of spells), or `'all'`. Default is `'var'`. `...` further arguments such as `digits` passed to the next `print` method.

### Details

The returned variance is a population variance, i.e. the sum of squares divided by the number of terms.

When `type=1`, this is the variance of the observed spells in the sequence. When `type=2`, in addition to the observed spells one spell of length 0 is considered for each non-visited state. The mean duration is computed the same way.

### Value

A numeric vector with the variance of spell duration of each sequence.

The returned object has two attributes:

 `vmax` the maximum value that the variance of each sequence could reach given its number of spells. `meand` the mean spell duration of each sequence.

### Author(s)

Gilbert Ritschard

### References

Ritschard, G. (2023), "Measuring the nature of individual sequences", Sociological Methods and Research, 52(4), 2016-2049. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1177/00491241211036156")}.

`seqdur`, `seqindic`

### Examples

``````sq.dat <- c('AAAA','AAAC','ABC','ABAA','AC')
sq <- seqdef(seqdecomp(sq.dat, sep=''), right=NA)

seqivardur(sq, type=1)
seqivardur(sq, type=1, with.missing=TRUE)
vd2 <- seqivardur(sq, type=2)
print(vd2, stat='all')
vd2m <- seqivardur(sq, type=2, with.missing=TRUE)
print(vd2m, stat=c('var','vmax'))

``````

TraMineR documentation built on May 29, 2024, 5 a.m.