# Data and statistics

Contents
In statistics, we try to make sense of the world by collecting, organizing, analyzing, and presenting large amounts of data. For example, you may survey your friends about what tv show is most popular, but the small sample size will not give you an accurate idea of what ALL 6th graders like to watch. To do this you must survey a cross section of students from all around the country and all backgrounds. The data can then be statistically analyzed to give a more accurate picture of what tv show is most popular. So let's dive into a discussion of statistics, including box and whisker plots, bar charts, pictographs, line graphs, and dot plots.

## Dot plots & frequency tables

A dot plot is like a bar chart, but it displays data using dots (not bars). And a frequency table is like a dot plot, but it displays data in a simple table (not a fancy diagram).

## Statistical questions

Statistics help us answer many questions, but not all questions are statistical. In this tutorial, we'll learn to tell the difference between a statistical question and a non-statistical question.

## Histograms

Histograms are similar to dot plots and bar graphs, but they work a little bit differently. In this tutorial, we'll learn how histograms work and when to use them.

## Mean and median

Mean and median are measures of "central tendency." That is, they help us find the center (or middle) of the data. In this tutorial, we'll learn how to compute mean and median.

## Mean and median challenge problems

Practice solving more challenging problems using your knowledge of mean and median.

## Interquartile range (IQR)

Interquartile range (IQR) is a tool for reasoning about the spread of data. Higher values of IQR tell you the data is more spread out. Lower values of IQR tell you the data is closer together.

## Box plots

Whether you're looking at scientific data or stock price charts, box-and-whisker plots can illuminate patterns in your life. This tutorial covers what they are, how to read them, and how to construct them.