---
title: "Using the samplex package"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Using the samplex package}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```r
# Load the package
library(samplex)

# Launch the Shiny app
samplex()
```

## Overview

The `samplex` package offers an interactive Shiny application to calculate sample sizes under various survey designs.

It includes methods for:

- Simple random sampling
- Stratified sampling (with proportional, Neyman, and optimal allocation)
- Single-stage cluster sampling

Users can set parameters such as confidence level, margin of error, population variance, average cluster size, intra-cluster correlation, and fixed costs, and receive real-time sample size outputs.

## Example use case: Cluster sampling for a proportion

Suppose a public health team wants to estimate the proportion of vaccinated students in rural schools.

The team can:

1. Open the app using `samplex()`.
2. Go to the *Cluster Sampling* tab.
3. Select "Proportion", and choose:
   - **Confidence level**: 95%
   - **Precision**: 0.04
   - **Estimated proportion**: 0.8
   - **Intra-cluster correlation (ICC)**: 0.01
   - **Average cluster size**: 100

The application will calculate the required sample size and number of clusters, and show formulas and summaries accordingly.