Critical Thinking and Testing Hypotheses Involving Two

Variables

Edward Nelson and Elizabeth Nelson

California State University Fresno

Sociology

Steps in Developing and Testing Hypotheses

• State the hypothesis

• Develop the argument or rationale that supports the hypothesis

• Create the dummy table

• Get the actual table

• Interpret the table and decide if it supports the hypothesis

State the Hypothesis

• A hypothesis states the expected relationship between two variables

• A hypothesis is testable– Definitions are not hypotheses– Moral imperatives are not hypotheses

• The hypothesis is the conclusion to the argument that supports it

Example of a HypothesisReligion and Opinion on Pornography Laws

Those who attend church frequently are more

likely to think there should be laws against the

distribution of pornography to everyone

regardless of their age.

Argument to Support Hypothesis

People who attend church frequently are more likely to have strong positions opposed to pornography and are, therefore, more likely to feel that society ought to make sure that pornography is not available to people regardless of their age.

Testing the Hypothesis

• To test this hypothesis we’ll use data from the 1998 and 2000 General Social Surveys. These surveys have been merged for this test.

• Data, codebook, and exercises are available on the Teaching Resources Depository-- http://www.cusbak.edu/ssric. Look for the data set RELG9800.

Dependent Variable--Wording of Question

• Which of these statements comes closest to your feelings about pornography laws?– There should be laws against the distribution of

pornography whatever the age.– There should be laws against the distribution of

pornography to persons under 18.– There should be no laws forbidding the

distribution of pornography to persons .

Dependent Variable-- Frequencies

Frequency Percent

Illegal to all 1390 37.0%

Illegal under 18 2230 59.4%

Legal to all 132 3.5%

Total 3752 100.0%

Dummy Table -- Opinions on Pornography by Church Attendance

Church Attendance

Feelings about porn laws

Often Sometimes Seldom

Illegal to all

a > b > c

Illegal under 18

d e f

Legal g h i

Table -- Opinions on Pornography by Church Attendance

Church Attendance

Feelings about porn laws

Often Sometimes Seldom

Illegal to all 60% 39% 25%

Illegal under 18 38% 59% 70%

Legal 2% 2% 5%

Chi square = 327.82, df = 4, sig < .0005 Gamma = .45 Source: General Social Survey, 1998 and 2000

Interpretation of Table• Those who attend church frequently are

more likely to feel that pornography ought to be illegal for everyone (60% of those who attend often compared to 25% of those who seldom attend).

• Those who seldom attend church are more likely to feel pornography ought to be illegal only for those under 18 (70% of those who attend infrequently compared to 38% of those who attend often).

Conclusion

• The analysis supports our hypothesis that the religious are more likely to feel that pornography ought to be illegal for everyone.

• However, we cannot conclude that frequent church attendance causes people to feel that pornography ought to be illegal to everyone.

• It’s possible that there is some other explanation than causality.