Statistics: Categorical Variables. Do Now: Give the context/ label the variables for the following...
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Transcript of Statistics: Categorical Variables. Do Now: Give the context/ label the variables for the following...
Do Now:Give the context/ label the variables for the following
situation:
The Federal Aviation Administration (FAA) monitors airlines for safety and consumer service. For each flight the carrier must report the type of aircraft, the number of passengers, whether or not the flights departed/arrived on schedule and any mechanical problems.
ObjectivesUnderstand different ways to display
categorical data.
Understand the ways these displays can be misleading.
Graphing Categorical Data:1. Frequency Table: records the totals and the
category names
2. Relative Frequency Table: displays the percentages, rather than the counts, of the values in each category.
How do we get percentages?
Other Options3. Bar Chart: displays the distribution of a
categorical variables, showing the counts for each category next to each other for easy comparison.
4. Relative Frequency Bar Chart: Guesses?
Other Options3. Bar Chart: displays the distribution of a
categorical variables, showing the counts for each category next to each other for easy comparison.
4. Relative Frequency Bar Chart: displays the distribution of categorical variables, showing the percentage for each category next to each other for easy comparison.
Alternatively5. Pie Charts: show the whole group of cases as
a circle. They slice the circle into pieces whose size is proportional to the fraction of the whole in each category.
Alternatively….Segmented Bar Graph: treats each bar as the
“whole” and divides it proportionally into segments corresponding to the percentages in each group.
Practice Problems:An article in the Winter 2003 issue of Chance
Magazine reported on the Houston Independent School District’s Magnet Schools program. Of the 1755 qualified applicants, 931 were accepted, 298 were waitlisted, and 526 were turned away for lack of space. Find the relative frequency distribution of the decisions made, and write a sentence describing it.
Follow Up QuestionThe Chance article also indicated that 517
applicants were Black or Hispanic, 292 were Asian, and 946 were White. Summarize the relative frequency distribution of ethnicity with a sentence of two.