# nsize: Required Sample Size In PASWR: Probability and Statistics with R

 nsize R Documentation

## Required Sample Size

### Description

Function to determine required sample size to be within a given margin of error

### Usage

```nsize(b, sigma = NULL, p = 0.5, conf.level = 0.95, type = c("mu", "pi"))
```

### Arguments

 `b` the desired bound `sigma` population standard deviation; not required if using type `"pi"` `p` estimate for the population proportion of successes; not required if using type `"mu"` `conf.level` confidence level for the problem, restricted to lie between zero and one `type` character string, one of `"mu"` or `"pi"`, or just the initial letter of each, indicating the appropriate parameter; default value is `"mu"`

### Details

Answer is based on a normal approximation when using type `"pi"`.

### Author(s)

Alan T. Arnholt <arnholtat@appstate.edu>

### Examples

```nsize(b = 0.015, p = 0.5, conf.level = 0.95, type = "pi")
# Returns the required sample size (n) to estimate the population
# proportion of successes with a 0.95 confidence interval
# so that the margin of error is no more than 0.015 when the
# estimate of the population propotion of successes is 0.5.
nsize(b = 0.02, sigma = 0.1, conf.level = 0.95, type = "mu")
# Returns the required sample size (n) to estimate the population
# mean with a 0.95 confidence interval so that the margin
# of error is no more than 0.02.

```

PASWR documentation built on May 15, 2022, 5:05 p.m.