# Using the samplex package

    # 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.