# n_dist.Student: Distribution of the Sample Size In blindrecalc: Blinded Sample Size Recalculation

 n_dist,Student-method R Documentation

## Distribution of the Sample Size

### Description

Calculates the distribution of the total sample sizes of designs with blinded sample size recalculation for different values of the nuisance parameter or of n1.

### Usage

``````## S4 method for signature 'Student'
n_dist(
design,
n1,
nuisance,
summary = TRUE,
plot = FALSE,
iters = 10000,
seed = NULL,
range = 0,
allocation = c("approximate", "exact"),
...
)
``````

### Arguments

 `design` Object of class `Student` created by `setupStudent`. `n1` Either the sample size of the first stage (if `recalculation = TRUE` or the toal sample size (if `recalculation = FALSE`). `nuisance` Value of the nuisance parameter. For the Student's t-test this is the variance. `summary` Is a summary of the sample size distribution desired? Otherwise, a vector with sample sizes is returned. `plot` Should a plot of the sample size distribution be drawn? `iters` Number of simulation iterations. `seed` Random seed for simulation. `range` determines how far the plot whiskers extend out from the box. If range is positive, the whiskers extend to the most extreme data point which is no more than range times the interquartile range from the box. A value of zero causes the whiskers to extend to the data extremes. `allocation` Whether the allocation ratio should be preserved exactly (`exact`) or approximately (`approximate`). `...` Further optional arguments.

### Details

The method is only vectorized in either `nuisance` or `n1`.

### Value

Summary and/or plot of the sample size distribution for every nuisance parameter and every value of n1.

### Examples

``````d <- setupStudent(alpha = .025, beta = .2, r = 1, delta = 3.5, delta_NI = 0,
alternative = "greater", n_max = 156)
n_dist(d, n1 = 20, nuisance = 5.5, summary = TRUE, plot = FALSE, seed = 2020)

``````

blindrecalc documentation built on Oct. 4, 2023, 5:06 p.m.