## Tuesday, July 26, 2011

### What is Statistics?

In one sense, statistics is a mindset -- a way of looking at things that occur in the world. These "things" are usually called data  or variables. Data can be numeric in ways that you can measure and label, like miles, dollars, feet, etc.; these are called quantitative variables. The other type of data is called categorical in that it is dividable into categories, like eye colors, levels of education, income ranges, etc.

Besides being a mindset, statistics is a set of methods for dealing with data. For example, we might have a list of stock prices for our favorite stock over the past month. We can find the average stock price, the maximum, the minimum, or the price that's smack in the middle (which is called the median). Don't worry about the meanings of all these terms...in time we will work with them all. Right now the important thing to know is that statistics consists of a Mindset and Methods.

Sometimes you have all the data in front of you and you want to analyze it; much like the stock prices above. This branch of statistics is called Descriptive Statistics. Other times, you only have some of the data and you want to draw reliable conclusions about all of the data. This branch of staitistics is called Inferential Statistics. An example of inference is the poll that tracks how many people watch various TV shows each week. Polling companies contact a subset of TV viewers using valid statistical methods that allow them to state with some confidence what TV shows we all are watching. You'd be surprised at how few viewers are needed (compared to all the viewers in the US)!

I am going to keep my posts short and sweet. My purpose, at the least, is to teach you a little bit about statistics in each post. My hopes are that I will demystify statistics for you and convince you that statistics doesn't have to be difficult. I will make this as fun and interactive as I can with real-life examples and self-quizzes. I look forward to working with you and getting your feedback to guide future posts!

Self Test: For now, select the word at the top of the page that best describes your feeling about statistics.