# Basic Statistics & Probability

#### Mean, Median, Mode & Range

The most commonly used statistic is the average, or finding where the middle of the data lies. There are three ways to measure the average: the mean, median, and mode. Why three ways? Goo...

#### Stem & Leaf Plots

Stem and Leaf Plots can be used to analyze data and display data all at the same time. This is a way of showing each data value along with its relationship to the other values.If you turn a...

#### Histograms

Histograms are another convenient way to display data. A histogram looks similar to a bar graph, but instead of plotting each individual data value on the x-axis (the horizontal one), a range o...

#### Box & Whisker Plots

Box-and-whisker plots are a handy way to display data broken into four quartiles, each with an equal number of data values. The box-and-whisker plot doesn't show frequency, and it doesn't displa...

#### Scatter Plots & Correlation

Scatter plots are an awesome way to display two-variable data (that is, data with only two variables) and make predictions based on the data. These types of plots show individual data values, a...

#### Basic Probability

We think it's highly likely that you've already dealt with probability today. Did you see the weather forecast? Is there a 30% chance of rain? Did you decide not to study for your foreign langu...

#### And vs. Or Probability

In probability, there's a very important distinction between the words and and or. And means that the outcome has to satisfy both conditions at the same time. Or means that the outcome has to s...

#### Complementary & Mutually Exclusive Events

Complementary events are two outcomes of an event that are the only two possible outcomes. This is like flipping a coin and getting heads or tails. Of course, there are no other options, so the...

#### Predicting vs. Observing Probability

There are two ways to calculate probability - either by using math to predict, or by actually observing the event and keeping score. Theoretical probability uses math to predict the outcomes. Just...

#### Compound Events

In the world of probability, compound events are probabilities of two or more things happening at once. For example, what is the probability that you forgot to do your homework and there will be a...

#### Basic Counting Principle

Now that you have learned all the hard ways to chart possible outcomes using organized lists, tree diagrams, and area models, it's time to learn the elegant short cut. Basic counting principle:...

#### Factorials

Factorials help count things like arrangements of items or order of events.
Let's say that you have six books to organize on your bookshelf...Use a factorial to count how many possible ways yo...