Chapter 1 – Stats start here

What is Statistics and data? Statistics: Data:

Examples – How dangerous is texting while driving? Researchers compare reaction time of sober drivers, drunk drivers, and texting drivers. The results were striking. The texting drivers actually responded more slowly and were more dangerous than those who were above the legal limit for alcohol – Target stores make customer profiles by collecting data about people using credit cards. Patterns the company discovers across similar customer profiles enable it to send you advertising and coupons that promote items you may be interested in purchasing. – Facebook: If you have a Facebook account you have probably noticed that the ads you see online tend to match your interests and activities. Much of your personal information has been sold to marketing or tracking companies. Your data are valuable! A company can find out your age, sex, education level, job, hobbies and activities.

What are Data? – Let’s start with an example: ________________ – Background: Amazon started as book store in By 1997 Amazon had 2.5 million books sold to more than 1.5 million customers in 150 countries. In 2010, sales reached 34.2 billion and they now sell basically everything, including a $400,000 necklace, Yak cheese from Tibet and the largest book in the world.

What are Data?

Context – Data must have ____________________________ – – What information provides good context?

The ______ – _______________________________________________ _________________________________________. For example, data that come from a voluntary survey on the Internet are almost always worthless. The _______  __________________– Data recorded in 1803 means something much different than data recorded now The ______  _____________ – data measured in India may be different than data measured in Mexico.  More specific – indoors/outdoors, house/office

The Who – In general the rows of a data table correspond to the individual cases about whom/which the data was collected, but cases go by different names depending on the situation: Individuals who answer a survey are called ______________________ People on whom we experiment are called _______________________________ In a database, the rows are called ________ Otherwise we call them what they are: customers, economic quarters, or companies, etc.

The What – – Can be broken into three categories:

The What – Identifiers – Everyone has a __________ ______ and they are useful for not confusing cases, but not needed to be analyzed. – Examples:

The What – Categorical Variables: – Usually text values, not numbers. Any descriptive responses are usually categorical. – Examples: – Numerical examples:

The What – Quantitative Variables: – The ________ provide a ___________ and also a scale in particular situations so we know how far apart two variables are. – Examples:

The What – Either/or: Some variables with ___________ values can be either categorical or quantitative depending on _______________________________ – Example: _______ _________________ – Amazon wants to know the average age of those customers that visit their site after 3 am. ________________ – When deciding which album to feature when you visit the site, they’ll have categories child, teen, adult, senior.

The What – Example – Identify each variable as categorical or quantitative. – A consumer reports article about 25 tablet computers lists each tablet’s manufacturer, cost, battery life (hours), operating system (iOS/Android), and overall performance score. Manufacturer – Cost – Battery life – Operating system – Performance score –

Example – Suppose a Consumer Reports article (published in June 2005) on energy bars gave the brand name, flavor, price, number of calories and grams of protein and fat. Identify the following Who: What: When: Where: How: Why: Categorical variables: Quantitative Variables (with units):