3.2 Visualizing Probabilities

Question 1

Tools for visualizing Probabilites

Answer 1

Contingency Tables, tree diagrams, Venn diagrams

Question 2

Contingency Tables

Answer 2

two-way tables summarize data about two categorical variables or factors collected on the same set of individuals

Question 3

Joint probabilities

Answer 3

a probability of outcomes for two or more variables or processes P(A n B)

Question 4

Marginal Distribution

Answer 4

studying the row totals and the column totals, they represent the marginal distribution, expressed in frequencies

Question 5

Marginal Distribution-relative frequency

Answer 5

found by taking the marginal frequencies and dividing by the grand total, often expressed as percentages or probabilities

Question 6

Conditional Distribution

Answer 6

the distribution of one factor for each level of the other factor

Question 7

conditional percent

Answer 7

is computed using the counts within a single row or a single column, the denominator is the corresponding row or column total rather than the table grand total

Question 8

Simpson’s Paradox

Answer 8

an association that holds for all of serval groups can reverse direction when the data are combined to form a single group

Question 9

Confounding or luring variabls

Answer 9

are always a problem for interpretation, but their impact can be even more drastic when dealing with categorical data

Question 10

tree diagram

Answer 10

helpful to define sample spaces, picture branching probabilities such as conditionals

Question 11

Compliment

Answer 11

P(A), P(A’)

Question 12

Mutually Exculsive

Answer 12

P(A), P(B)

Question 13

Not mutually exclusive

Answer 13

P(A n B), P(A)=PP(A n B’)+P(A n B), P(B)=P(B n A’)+P(A n B)