Calculadora de Polígono de Frequência

The Frequency Polygon Calculator is a statistical tool that helps in constructing frequency graphs. It calculates the relative frequency of each class or value in a dataset by dividing the absolute frequency by the total number of observations. The result is expressed in decimal or percentage form, allowing visualization of each category's proportion relative to the whole. This calculation is essential for creating frequency polygons, which are line graphs connecting the midpoints of classes at the top of their frequencies.

How it works: the formula used is fr = f / n, where 'fr' is the relative frequency, 'f' is the absolute frequency (number of occurrences in a class), and 'n' is the total number of data points. The user enters the absolute frequencies for each class and the total observations. The calculator processes the data and returns the corresponding relative frequencies. This procedure is fundamental for comparing distributions of different sample sizes, as it normalizes data to a common scale.

When to use: this calculator is useful in statistical analysis, academic research, market studies, and any situation involving the distribution of categorical or grouped continuous data. For example, a teacher can use it to display the distribution of class grades; a quality analyst, to evaluate the frequency of defects in batches; or a researcher, to compare the occurrence of responses across groups. The resulting frequency polygon helps identify patterns, trends, and outliers.

Common precautions: ensure that the absolute frequencies sum exactly to the total provided, otherwise calculations will be incorrect. The calculator assumes data are mutually exclusive and exhaustive. For class intervals, remember to use the midpoint of each class when plotting the graph. Relative frequency is sensitive to rounding; prefer consistent decimal places. Avoid comparing frequency polygons with different numbers of classes without standardization.