# Tag Archives: One categorical variable

## Confidence interval for a single proportion

A confidence interval gives an estimated range of values which is likely to include an unknown population parameter, the estimated range being calculated from a given set of sample data, as this site puts it. This site says statisticians use a confidence interval to describe the amount of uncertainty associated with a sample estimate of a population parameter.  They are used […]

## Hypothesis Test for a Single Proportion

A hypothesis test for a single proportion measures the proportion of a sample taken from the population for a given trait in order to infer information about the proportion of that trait in the whole population itself.  The hypothesis test for a single proportion is a test of two contradictory hypotheses about the proportion of the […]

## Bar Graphs

A Bar Graph is a method of displaying categorical data for comparison, with one axis representing the categories and the other representing discrete values. These discrete values are a measure of frequency. These axes may be switched, resulting in two kinds of bar graphs. Bar graphs have either horizontal or vertical bars, depending on where the categorical […]

## Bar Graphs

A Bar Graph is a method of displaying and comparing discrete data sets. Bar graphs display categories as rectangles whose height (if vertically displayed) or length (if horizontally displayed) are proportional to each other by the proportionality of the data they are displaying. The graph shown displays the number of dog owners per breed in a sample with a […]

## Pie Charts

A pie chart is a circular graphical display for a single categorical variable. The graph is divided into segments, each representing a particular category. Each segment is the same proportion of a circle as the category is of the total data set. The percentages in the pie chart must add up to 100%. Pie charts […]

## Frequency Tables

A frequency table lists each group of data and the number of occurrences for each category of data. The groups are usually categories (such as car color), intervals (as seen on the right), or values (like number of cars) that will be recorded in the first column. If the classes are numerical, then they need to be […]

## Bar Graphs

A bar graph is a graph drawn using rectangular bars to show how large each value is. One could use a bar graph to show how something varies over time or to contrast items as described here. While a bar graph is visually easy to understand, the disadvantages, from this site, would be that graph […]