Exam 2 Two-Way tables Flashcards Preview

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Flashcards in Exam 2 Two-Way tables Deck (15):
0

Association

Values of one variable tend to occur with certain values of another variable; detected when the conditional distributions differ from the marginal distributions and from each other.

1

Bias

The design of a statistical study is biased if it is systematically favors certain outcomes.

2

Bivariate data

Data collected on two variables for each individual in a study.

3

The only arithmetic operation that makes sense for categorical data is

Counting

4

Two-Way table is a

Table giving counts (or %) for two categorical variables

5

In two-way tables the ..... Is is a row variable, and ...... Is the column variable

Explanatory ....response

6

Marginal distribution

Distribution of column variable separately ( or row variable separately ) expressed in counts or percent

7

Both margins sum to the

Same overall total

8

Conditional Distributions

Distribution of percents under a specific condition ( either in row or column)

9

There is no association between categorical variables when all

Conditional distributions look like the marginal distribution and each other

10

There is a potential association between categorical variables when

One or more of the conditional distributions look very different from the marginal distributions or each other

11

Simpson's paradox happens

When the third lurking variable is associated with the other two.

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What is Simpson's paradox

A situation where the relationship between two variables is in one direction when the third lurking variable is included but in the opposite direction when the the third lurking variable is ignored.

13

Measures affected by outliers

Mean
Standard deviation
Correlation
R-sq
Slope and y-intercept

14

Rules of Data Analysis

1. Always plot your data
2. Always describe shape, center, spread of distributions
3.Don't use the normal distribution to mod data that is not normal
4. Always draw and label the normal curve when finding % of x values
5. For Bivariate data, always examine a Scatterplot before computing r or modeling with a least squares regression equation