# Probability and Statistics Examples

#### Mode

The phrase "a la mode," used today to mean "with ice cream," literally means "in the fashion." As we know, there's nothing more fashionable than ice cream. In statistics, the mode of a set of da...

#### Mean/Average

When thinking about averages, we like to think about cookies. Okay, we always like to think about cookies...averages are only a convenient excuse.Suppose Paul has 3 cookies and Mary has 5. That...

#### Median

The median of a list of numbers is the "middle" number. To find the median, first we put our list of numbers in order. Then we cross off pairs of numbers (one from the top of the list and one fr...

#### Quartiles

Quartiles are numbers that break a list of data up into quarters ("quarters,'' "quartiles''...makes sense, right?). We're totally stuffed full of cookies at the moment, so let's turn our attentio...

#### Bar Graphs and Histograms

Remember the difference between discrete and continuous data: discrete data has clear separation between the different possible values, while continuous data doesn't. We use bar graphs for displayi...

#### Pie Charts/Circle Graphs

Pie Charts, also known as circle graphs, are ways of displaying the proportions, or percentages, of data that fall into different categories. It makes sense that these graphs are useful for displ...

#### Box and Whisker Plots

A box and whisker plot for a list of numbers is a picture built on a number line that uses five numbers: the lowest and highest values in the list, and the quartiles Q1, Q2, and Q3. Try not to s...

#### Scatter Plots

A common way of displaying bivariate data when both variables are quantitative is using a scatter plot. A scatter plot has a title, axes with labels, and (exactly like it sounds) little dots scatte...

#### Outcomes and Events

Whenever we do an experiment like flipping a coin or rolling a die, we get an outcome. For example, if we flip a coin we get an outcome of heads or tails, and if we roll a die we get an outcome o...

#### Important Elements

The probability of an eventis a fraction: is non-negative (that is, 0 or greater). There's no such thing as a negative number of outcomes. cannot be more than 1. There can't be more...

#### Odds

The probability of an event is written as a fraction:This probability tells us how likely an event is to happen.Odds are another way of conveying the same information, or another way of saying ho...

#### Compound Events

A compound event is an event that can be described in terms of simpler events, not a riot that occurs on prison grounds. A compound event will often, but not always, involve multiple experiments....

#### Independent and Dependent Events

Suppose we have a jar with 10 pieces of chocolate candy and 5 pieces of vanilla candy. Clearly, the chocolate candy is far superior, which is why we went out and bought twice as many of them.We...

#### Mutually Exclusive Events

These aren't parties that only mutual fund managers are allowed to attend. Don't worry; you aren't missing much. Not too much roof-raising goes on at those shindigs.
Sometimes two events can't...

#### Factorials and Permutations

Let's say we have two books: The Odyssey and The Iliad. We should probably have more books, but if we're only going to have two, these are a good two to have. There are two possible ways to order t...

#### More Probability

Now that we can find numbers of permutations and combinations, we can find more complicated probabilities.Sample ProblemA jar contains 5 vanilla candies, 9 spice candies, and 3 shrimp candies. That...