Warm Up
 Sam scored the following grades on his exams
 51%
 62%
 70%
 39%
 81%
 57
What is Sam’s exam average?
LEQ: What is the difference
between categorical and
quantitative data?
Data
 Write two complete and grammatically correct
sentences explaining your primary reason for taking
this course and then describing what the term
statistics means to you.
 For each word in your response, record the number
of letters in the word.
Data
The numbers that you have recorded are data. Not all
numbers are data, however. Data are numbers
collected in a particular context.
Example: The #’s 10, 3, and 7 are not data on their
own, BUT if we are referring to the number of letters
in the first three words of the responses you wrote.
Data
 Even though you all had to count the same thing, the
number of letters in the first three words, many of
you have different results.
 This shows us one of the most important ideas of
this class VARIABILITY.
 What is variability?
Variability
 Variability refers to the phenomenon of a variable
taking on different values or categories from
observational unit to observational unit.
 For the data that you just collected, the observational
units (the subject) were the words. What was the
variable? i.e – What varied in our data?
What do you think the definition is?
Categorical
Quantitative
Model of a car
Weight
Gender
Length in inches
Yes or no
Time in seconds
Pass or fail
# of questions right on a quiz
Write it out
!
 Categorical Data:
 Falls into a category.
 Example: Ask 20 people what color their car is
(brown/blue/green/red/black…?)
 Quantitative Data:
 Has a known unit. The unit could be a time, length, degree,
mean, standard deviation etc. (ANYTHING that is a numerical
value)
 Example: Ask 20 people how tall they are.
LEQ: What is the difference between
categorical and quantitative data?
With your partner, decide whether or not each data type is
categorical or quantitative.
 A rating system of superior/good/average/poor C
 Time in second to run a mile Q
 Social Security Numbers
C
 Student test grades ranging from 1 to 100 Q
 Heights of people recorded in inches Q
 Zip codes C
 Percentage of students who have mastered a skill. Q
LEQ: What is the difference between
categorical and quantitative data?
Lets fix our definitions…
 Categorical Data:
 Falls into a category.
 Example: Ask 20 people what color their car is
(brown/blue/green/red/black…?)
 Quantitative Data:
 Has a known unit. The unit could be a time, length, degree,
mean, standard deviation etc. (ANYTHING that is a numerical
value)
 Example: Ask 20 people how tall they are.
LEQ: What is the difference between
categorical and quantitative data?
Depends on how you put it…
Consider yourselves the observational units. Classify
each of the following variables as categorical or
quantitative.
 How many hours have you slept in the past 24
hours?
 Whether you have slept for at least 7 hours in the
past 24 hours.
Binary Data
Your turn!
 With a partner, please take out the data collected
sheets you used yesterday in class and decide if
each question is either quantitative or categorical.
 If it is categorical, decide if it is binary.
Exit Ticket
 Come up with your own example (THAT WE HAVE
NOT USED TODAY) of each of the following:

Categorical Data (Not Binary)

Categorical Data (Binary)

Quantitative Data