Individuals

1
Individuals

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

2
Variable

• It is any characteristic of an individual.
• It can take different values for different
  individuals.
• Example High schools student data base.

3
New Data SetQuestions 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?

4
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

5
Quantitative or Qualitative?
Qual

• Voters region (North, South, etc)

• Age (in years)

Qual

• Systolic Blood pressure (mm of mercury)

Quan

• Level of calcium in the blood (micrograms/ml)

Quan

• Smoker (yes or no)

Qual
6
Survey

• Identify the type of each variable

7
www.censusatschool.com

• Hundreds of thousands of students from Australia,
  Canada, New Zealand, South Africa, and the United
  Kingdom.
• Lets pick 10 students

8
Who are the Individuals in this data set?
9
What variables were measured?Identify each as
categorical or quantitative.In what units were
the quantitative variables measured?
10
Describe the individual in the highlighted row.
11
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.

12
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 cars 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?

13
Inference

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

14
Activity Airlines Discrimination

• Each group of 4 will split into 2 to do the
  activity and 4 to discuss.

15
Activity How Long is a minute
16
Homework

• Page 7 (1, 3, 5, 6, 7, 8)