Lesson 4 Flashcards
Qualitative
Qualitative (aka categorical) data consists of values that can be placed into non-numeric
categories. In some cases, these variables may look like numbers, but the numbers serve as
labels that could be replaced by letters (or symbols) if we wanted. In other words,
qualitative variables do not have a numeric meaning.
Quantitative
Quantitative (aka numerical) data consists of values that represent counts or measurements.
These values have numeric meaning, and it would make sense to compare them on a
number line as a smaller or larger. Also, it makes sense to calculate the average value.
Quantitative examples
Hours of sleep
(e.g. 7.25), Shoe size, The number of
colleges applied
Qualitative examples
Favorite color, Blood type
(A, B, AB, or O), Happiness level
(unhappy, ok, or
awesome), Zipcode
What is discrete
If the variable can only take on certain
values (and not others in between) it is
called discrete.
What is continuous
If the variable can take on any value in
an interval it is called continuous.
discrete and continuous are…
Quantitative
Discrete examples
Hours of sleep
(e.g. 7.25)
Continuous example
Shoe size, The number of
colleges applied
There are 4 different
measurement scales:
Nominal, Ordinal,
Interval, and Ratio
Qualitative data can be
nominal or ordinal.
Quantitative data can be
interval or ratio
Qualitative variables with a natural
ordering are said to be
ordinal.
Qualitative variables without a natural
ordering are said to be
nominal.
Nominal and ordinal are…
qualitative
Examples of nominal..
Blood type
(A, B, AB, or O),Favorite color,Zip code,
Examples of ordinal..
Steak
preference
(rare to well
done), Happiness level
(unhappy, ok, or
awesome)
Interval level
A scale used to label quantitative variables that have a natural order and a
quantifiable difference between values, but no “true zero” value.
Ratio level
A scale used to label variables that have a natural order, a quantifiable
difference between values, and a “true zero” value.
Ratio level and interval level are..
Quantitative
Examples of interval
Shoe size
Examples of ratio
Hours of sleep
(e.g. 7.25), The number of
colleges applied
Suppose a researcher wants to know how adult American acts in their normal life related
to a study of germs. In a survey, 1234 subjects were asked if they ever hesitated to give a
handshake because of a fear of germs. Of these respondents, about 72.5% answered
“yes.”, about 25% answered “no.”, and about 2.5% answered ‘not sure’.
* Are the numbers 72.5%, 25%, and 2.5% considered as a raw data?
* What would be the raw data look like?
* Is the raw data considered quantitative or qualitative?
* What is the level of measurement of the data?
- No, those numbers are statistics.
- The raw data is the survey responses. It includes only one of the responses as yes, no, or
not sure. - Qualitative data.
- Nominal level of measurement.
Of the all 2,223 people who were aboard the Titanic, 31.76% survived when
the ship sank on Monday, April 15, 1912. What is the population? What is the sample?
* Is the number 31.76% a raw data, a sample statistic, or population
parameter? Why?
* Is this an observational study or experiment?
* What is the variable of interest in this case?
* Is the variable quantitative or qualitative? Is it discrete or continuous?
* What is the level of measurement of the variable?
Population: The all 2,223 people who were abroad the Titanic
* Sample: None (No sample has been selected)
* 31.76%: Population parameter since it is a number obtained from the
population.
* It is an observational study
* Variable of interest: Whether the person survived or died
* It is qualitative. Not valid to say discrete or continuous for a qualitative.
* Level of measurement: Nominal
