3-4-1. Descriptive Statistics – Part I

When analyzing both discrete and continuous quantitative data, we generally discuss four main aspects. The center, the spread, the shape and outliers. In this lesson, we will focus on measures of center. There are three widely accepted measures of center. The mean, the median and the mode. To illustrate how each of these measures is … Read more

In the next lessons, we will discuss how to use statistics to describe quantitative data. You will gain insight into a process of how data is collected and how to answer questions using your data. Throughout this lesson, I hope you learn to be critical of your analysis that happened under the hood and what … Read more

To summarize, we have two main data types, each with two subgroups. Quantitative data can be divided into continuous and discrete. Categorical can be split into nominal and ordinal. Identifying data types is important, as it allows us to understand the types of analyses that we can perform and the plots that we can build. … Read more

We can also divide quantitative data types further. I assume most of my positive interactions occur with older dogs, as they’ve had more time to train. The age of a dog is a continuous quantitative data type, while the number of dogs I interact with is a discrete quantitative data type. In the world, we … Read more

We can divide categorical data types further into categorical ordinal and categorical nominal. First, let’s look at categorical ordinal data. Remember those dogs at the coffee shop? Let’s say I give each a rating of how nice it is to me. Sometimes I shake hands with the dog and we become best friends. Other times, … Read more

In this video, we’ll be taking a look at the different data types that exists in the world around us. When sitting at coffee shops, I enjoy watching the dogs pass. I often wonder, how many crossed my path? I wonder if more pass on weekdays or weekends. Maybe the number differs from Mondays to … Read more

The word “data” is defined as distinct pieces of information. You may think of data as simply numbers on a spreadsheet, but data can come in many forms. From text to video to spreadsheets and databases to images to audio, and I’m sure I’m forgetting many other forms. Utilizing data is the new way of … Read more

A quick overview leading up to your first project. We will start with an overview of data types and the most common statistics used when analyzing data. We’ll discuss measures of center and spread. The most common shapes that data takes on and how to handle outliers. You will take this farther by using spreadsheets … Read more

But now, if we want to sum all the values in our original example, we no longer need to write out all of the xs. Instead, we can write our summation starting at i=1 and ending at the fifth value. This is way better when wanting to extend to 10 or 20 or even 100 … Read more

There are common ways to notate most aggregations. An aggregation is just a way to turn multiple numbers into fewer numbers, usually just one number. Common aggregations include the measures of center we introduced earlier, like the mean, the median, and the mode. Each of these takes many numbers and provides a single value to … Read more

In the next concepts, we are going to combine what we know about how to calculate the mean with notation. The purpose of this video is not to relearn how to calculate the mean but rather to introduce notation using a measure you already know. Let’s consider the amount of time someone spends on our … Read more

Connecting this full circle, these capital letters X and Y relate to a random variable. This is an abstract idea. How much time an individual spends on our website, can take on lots of different values. So, this capital letter X is not a number, it’s an entire set of possible values. We can think … Read more

As a first example, let’s apply this new idea of notation to something you’ve used before. Spreadsheets. Spreadsheets are a common way we hold data in the real world. In our spreadsheet, we have rows and columns. To better understand how we use spreadsheets to hold data, let’s work through an example. Before even collecting … Read more

Previously, we listed the four main aspects of analyzing quantitative data; center, spread, shape and outliers. We also looked specifically at measures of center, by introducing means, medians and modes. Before we look at measures of spread, it’s important to understand notation. You might not even know it, but you use notation all the time. … Read more

The third measure of center, aims at providing us the most common value in the data set. In this data set, this is the value of three. The value that occurs most often is known as the Mode. These are all three potential measures of center. The Mean or the average, the Median or the … Read more

A more appropriate measure in this case, might be the median. The median is a value that divides our data set such that 50% of the values are larger while the remaining 50% are smaller. For our data set, we have a median of eight. This is a much better response than the 12 and … Read more

Statistics is at the core of analyzing data. For the stats portion of this class, you’ll be learning from Sebastian Thrun and Josh Bernhard. Sebastian is a statistician and Stanford faculty member, as well as founder of Udacity and Google X. He’ll be showcasing a number of examples for each of the statistical topics covered. … Read more