Individuals The individuals are the objects described by a set of data. Individuals may be people, animals, or things. It’s the who or what that we are studying.

Variable It is any characteristic of an individual. It can take different values for different individuals. Example: High school’s student data base.

New Data Set…Questions to ask yourself. Who are the individuals described by the data? How many individuals are there? What are the variables? In what units is each variable?

Types of Variables Categorical – also known as qualitative  Data from individual is placed into a category Quantitative – also know as numerical  Takes numerical values and it makes sense to find an average

Quantitative or Qualitative? Voter’s region – (North, South, etc) Age – (in years) Smoker – (yes or no) Systolic Blood pressure (mm of mercury) Level of calcium in the blood (micrograms/ml) Quan Qual

Hundreds of thousands of students from Australia, Canada, New Zealand, South Africa, and the United Kingdom. Let’s pick 10 students…

Who are the Individuals in this data set?

What variables were measured? Identify each as categorical or quantitative. In what units were the quantitative variables measured?

Describe the individual in the highlighted row.

Distribution The distribution of a variable tells us what values the variable takes and how often it takes these values. It represents the pattern of variation of a variable.

Jake is a car buff who wants to find out more about the vehicles that students at his school drive. He gets permission to go to the student parking lot and record some data. Later, he does some research about each model of car on the Internet. Then he makes a spreadsheet that includes each car’s model, year, color, number of cylinders, gas mileage, weight, and whether is has a navigation system. Who are the individuals? What variables did he measure?

Inference Drawing conclusions that go beyond the data at hand. Using a sample group to discuss the population.

Activity – Airlines Discrimination Each group of 4 will split into 2 to do the activity and 4 to discuss.

Survey

Activity – How Long is a minute

Homework Page 7 (1, 3, 5, 6, 7, 8)