CHAPTER 3: DISPLAYING AND DESCRIBING

CATEGORICAL DATA

Make a picture!!!

_______ clearly_______ the patternBest way to _______

Categorical Data

Mathematics of Categorical Data –

Displaying Categorical Data –

Frequency Table

A table recorded with organized ________ of each category.

Difference between Frequency Table vs. Relative Frequency Table?

Similarities between Frequency Table & Relative Frequency Table?

Frequency Table * Rel. Frequency Table

GRADE # of STDTS

Grade 9 411

Grade 10 405

Grade 11 387

Grade 12 394

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Relative Frequency Table

GRADE

GRADE 9

GRADE 10

GRADE 11

GRADE 12

% of Students

BAR GRAPHS

Displays the distribution of a ___________ variable, showing the counts for each __________ next to each other for easy comparison.

________ between bars.Can be ________/__________ bars.Relative Frequency Bar Chart (Graph):

has the bar as a __________/__________ instead of a count.

PIE CHART

Displays each group of cases as a __________/_________ of the whole.

Quick impression of how a whole group is ___________ into smaller groups.

Good for seeing relative frequencies near ½, ¼, or 1/8.

CONTINGENCY TABLES

Two-way table (for two categorical variables)Marginal Distribution

First Second Third Crew Total

Alive 203 118 178 212

Dead 122 167 528 673

Total

Class

Sur

viva

l

Conditional Distribution

Distribution of one variable for just the individuals who satisfy some condition on another variable.

First Second Third Crew Total

Alive 203 118 178 212 711

Class

First Second Third Crew Total

Alive 203 118 178 212 711

Dead 122 167 528 673 1490

Total 325 285 706 885 2201

ClassS

urvi

val

“What percent of the survivors were in second class?”

“What percent were second-class passengers who survived?”

“What percent of the second-class passengers survived?”

Independence

Variables are independent of each other when the distribution of one variable is _______________ for all categories of another.

JUST CHECKING~ See Handout

BLUE BROWN OTHER TOTAL

MALES 6 20 6 32

FEMALES 4 16 12 32

TOTAL 10 36 18 64

Eye Color

Se

x

~Just Checkin’~

Homework

Read the rest of chapter 3 and outlineP36 #5-7, 9, 11, 14, 19

Segmented Bar Charts

Treats each bar as a “whole” and divides it __________________ into segments corresponding to the ____________ in each group.

Examining Contingency Table – THINK

PLAN – Be sure to state what the problem is about.

VARIABLES – reports the ____

- Categorical? Quantitative?CHECK for ________________________

SHOW

Check marginal distributionTwo-way table (contingency table)Bar/Pie chartCompare results

TELL

Interpret the pattern in the table and displays in _____________.

SIMPSON’S PARADOX

It’s the last inning of an important game.

Your team is a run down with the bases

loaded and two outs. The pitcher is due up,

so you’ll be sending in a pinch-hitter. There

are 2 batters available on the bench. Whom

should you send in to bat?

Player Overall

A 33 for 103

B 45 for 151

Player Overall vs LHP vs RHP

A 33 for 103 28 for 81 5 for 22

B 45 for 151 12 for 32 33 for 119

How about now?

Which company would you want to work for?

HOMEWORK

P38 #18-22 even, 39, 40Read thru the investigation Study for QUIZ