1. Name 2 things in the classroom that are considered categorical data.
Name 2 things in the classroom that are considered quantitative data.
Warm - Up # 4

2. Unit 8: 2 Variable Statistics
EQ1: How can we organize categorical data and compare and contrast joint frequencies and marginal frequencies.
Two Way Table

3. Average blood pressure Favorite TV Show
Homework Check
Quantitative
Categorical
Average blood pressure
Favorite TV Show
Age group
Population
Common majors in college
Hours spent outdoors each day
Average calories consumed in a day
Who received high school diplomas
Number of brothers and sisters
Hours spent doing HW each night
Whether or not people smoke
Time of day you go to bed
Right-handed or left-handed
Height
Gender
Miles from home to school
Favorite food
Shoe size

4. Two-Way Tables
Two-Way tables show the relationships between two categorical variables. A two-way table has a column variable and a row variable.
Column Variables go up and down
Row Variables go left and right
Make a decision as to which of the column variables do you prefer!
Vine
Twitter
Instagram
Total
Male
Female

5. There are two types of frequencies included in the table: joint frequencies and marginal frequencies.
joint frequencies represent the body of the table marginal frequencies represent the total row and total column. Note: Sample Size : is the total number of individuals surveyed.

6. There are two types of frequencies included in the table: joint frequencies and marginal frequencies.
Vine
Twitter
Instagram
Total
Male
Number of males who prefer Vine
Number of males who prefer Twitter
Number of males who prefer YouTube
Total number of males
Female
Number of females who prefer Vine
Number of females who prefer Twitter
Number of females who prefer YouTube
Total number of females
Total number of people who prefer Vine
Total number of people who prefer Twitter
Total number of people who prefer YouTube
Total people surveyed
“Sample Size”

7. Job Opportunity
Apple needs you! They are planning to promote the iPhone and iPad in a new series of commercials. Based on our data, should the ad focus on the use of Vine, Twitter, or Instagram apps? Why? What other factors would impact your decision?

8. SURVEY SAYS….
Let’s take a class poll and fill in our two-way table to help Apple’s marketing department. Of the three choices, which site do you visit most often when online?
Vine
Twitter
Instagram
Total
Male
Female

9. What does this all mean? Interpreting Joint Frequencies
# of males prefer Vine_________
# of females prefer Vine_________
# of males prefer Twitter _________
# of females prefer Twitter _________
# of males prefer Instagram _________
# of females prefer Instagram _________

10. What does this all mean? Marginal Frequencies
Total # of people prefer Vine. _________
Total # of people prefer Twitter. _________
Total # of people prefer Instagram. _________
Total # of males surveyed. _________
Total # of females surveyed. _________

11. Joint Probabilities are used to give meaning to the two-way table.
are percentages for each element compared to the whole
Typically used when sample size (# of people asked) is not given.
To find the joint probability for each element of the table, divide the frequency by the total.
Round to the nearest hundredth!

12. Original Two-Way Table Joint Probability
Vine
Twitter
Instagram
Total
Male
Female
Vine
Twitter
Instagram
Total
Male
Female
100%

13. In Other Words…
_______ % of males prefer Vine. _______ % of females prefer Vine. _______ % of males prefer Twitter. _______ % of females prefer Twitter. _______ % of males prefer Instagram. _______ % of females prefer Instagram.

14. So What?
Data collection’s purpose is to answer a hypothesis. (A Question) What kind of questions does this answer?
Do males spend more time than females on Twitter?
Do females spend more time on Vine than anything else?

15. Use the information collected to defend your answer!
What should Apple do?
Based on our data, should the
ad focus on the use of
Vine, Twitter, or
Instagram apps? Why?
Use the information collected to defend your answer!