chapter 12 bivariate association: introduction and basic concepts
TRANSCRIPT
![Page 1: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/1.jpg)
Chapter 12
Bivariate Association: Introduction and Basic Concepts
![Page 2: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/2.jpg)
Introduction Two variables are said to be associated
when they vary together, when one changes as the other changes.
Association can be important evidence for causal relationships, particularly if the association is strong.
![Page 3: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/3.jpg)
Introduction
If variables are associated, score on one variable can be predicted from the score of the other variable.
The stronger the association, the more accurate the predictions.
![Page 4: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/4.jpg)
Association and Bivariate Tables
Bivariate association can be investigated by finding answers to three questions: Does an association exist? How strong is the association? What is the pattern or direction of the
association?
![Page 5: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/5.jpg)
Association and Bivariate Tables: Problem 12.1 The table shows the relationship between
authoritarianism of bosses (X) and the efficiency of workers (Y) for 44 workplaces.
Low Author. High Author.
Low Efficiency 10 12 22
High Efficiency 17 5 22
27 17 44
![Page 6: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/6.jpg)
Is There an Association? An association exists if the conditional
distributions of one variable change across the values of the other variable.
With bivariate tables, column percentages are the conditional distributions of Y for each value of X.
If the column % change, the variables are associated.
![Page 7: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/7.jpg)
Association and Bivariate Tables The column % is (cell frequency / column total) * 100. Problem 12.1:
(10/27)*100 = 37.04% (12/17)* 100 = 70.59% (17/27)*100 = 62.96% (5/17)*100 = 29.41%
Low Author. High Author.
Low Effic
10 (37.04%) 12 (70.59%) 22
High Effic
17 (62.96%) 5 (29.41%) 22
27 (100.00%) 17 (100.00%) 44
![Page 8: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/8.jpg)
Is There an Association? The column %s
show efficiency of workers (Y) by authoritarianism of supervisor (X).
The column %s change, so these variables are associated.
Low Auth
High Auth
Low Effic
37.04% 70.59%
HighEffic
62.96% 29.41%
100% 100%
![Page 9: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/9.jpg)
How Strong is the Association?
The stronger the relationship, the greater the change in column %s (or conditional distributions). In weak relationships, there is little or no
change in column %s. In strong relationships, there is marked
change in column %s.
![Page 10: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/10.jpg)
How Strong is the Association? One way to
measure strength is to find the “maximum difference”, the biggest difference in column %s for any row of the table.
Difference Strength
Between 0 and 10%
Weak
Between 10 and 30%
Moderate
Greater than 30%
Strong
![Page 11: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/11.jpg)
How Strong is the Association? The Maximum
Difference in Problem 12.1 is 70.59 – 37.04 = 33.55.
This is a strong relationship.
Low Auth.
High Auth.
LowEffic
37.04% 70.59%
HighEffic
62.96% 29.41%
100% 100%
![Page 12: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/12.jpg)
What is the Pattern of the Relationship?
“Pattern” = which scores of the variables go together?
To detect, find the cell in each column which has the highest column %.
![Page 13: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/13.jpg)
What is the Pattern of the Relationship?
Low on Authoritarianism goes with High on efficiency.
High on Authoritarianism goes with Low in efficiency.
Low High
Low 37.04 % 70.59 %
High 62.96 % 29.41 %
100% 100%
![Page 14: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/14.jpg)
What is the Direction of the Relationship?
If both variables are ordinal, we can discuss direction as well as pattern.
In positive relationships, the variables vary in the same direction. As one increases, the other increases.
In negative relationships, the variables vary in opposite directions. As one increases, the other decreases.
![Page 15: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/15.jpg)
What is the Direction of the Relationship? Relationship in
Problem 12.1 is negative.
As authoritarianism increases, efficiency decreases.
Workplaces high in authoritarianism are low on efficiency.
Low High
Low 37.04 % 70.59 %
High 62.96 % 29.41 %
100% 100%
![Page 16: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/16.jpg)
What is the Direction of the Relationship? This relationship is
positive. Low on X is
associated with low on Y.
High on X is associated with high on Y.
As X increase, Y increases.
Low High
Low 60% 30%
High 40% 70%
100% 100%
![Page 17: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/17.jpg)
Summary: Problem 12.1 There is a strong,
negative relationship between authoritarianism and efficiency.
These results would be consistent with the idea that authoritarian bosses cause inefficient workers (mean bosses make lazy workers).
What else besides association do you need to show causation?
Low Auth
High Auth
Low Effic
37.04% 70.59%
High Effic
62.96% 29.41%
100% 100%
![Page 18: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/18.jpg)
Correlation vs. Causation Correlation and causation are not the same
things. Strong associations may be used as
evidence of causal relationships but they do not prove variables are causally related.
What else would we need to know to be sure there is a causal relationship between authoritarianism and efficiency?
![Page 19: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/19.jpg)
Criteria for bivariate causation
1. Association between variables 2. Time order 3. Lack of spuriousness
![Page 20: Chapter 12 Bivariate Association: Introduction and Basic Concepts](https://reader036.vdocuments.site/reader036/viewer/2022082917/5519b1355503467a578b45d8/html5/thumbnails/20.jpg)
Sometimes time order is easy; sometimes it’s not. Which comes first,
inefficient workers or authoritarian bosses
Also possible that inefficient workers produce authorit. bosses
Low Effic
HighEffic
Low Auth
12 50%
1777.2%%
HighAuth
12 50%
5 22.8%
24100%
22 100%