Two Way Table

Warm - Up #

Homework Using the worksheet you have given, place each statement in the appropriate place. Average blood pressure Who received high school diplomas Right-handed or left-handed Favorite TV show Hours spent outdoors each day Time of day you go to bed Age group Whether or not people smoke Favorite food Common majors in college Average calories consumed in a day Gender Population Number of brothers and sisters Height Shoe size Hours spent doing HW each night Miles from home to school

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

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! Facebook Twitter Instagram Total Male Female

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. “In the margins” Note: Sample Size : is the total number of individuals surveyed.

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

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 Facebook, Twitter, or Instagram apps? Why? What other factors would impact your decision?

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? Facebook Twitter Instagram Total Male Female

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

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

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!

Original Two-Way Table Joint Frequencies Facebook Twitter Instagram Total Male Female Facebook Twitter Instagram Total Male Female 100%

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

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 Facebook than anything else?

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