Ch 9: Test Yourself

3d human with a red question mark

(1) Test Yourself in Choosing a Statistic (a good way to review the last several chapters and when to use which statistic).

(2) Here are some results from a linear multiple regression, analyzing which independent variables can explain or predict the age when respondents (in the General Social Survey) first marry. Independent variables include sex  (1=male, 2=female), highest year of school completed (number of years), and attitudes toward premarital sex (1=always wrong to 4=not wrong at all).

Model Summary

Model

R

R Square

Adjusted R Square

Std. Error of the Estimate

1

.310a

.096

.096

4.525

a. Predictors: (Constant), SEX BEFORE MARRIAGE, RESPONDENTS SEX, HIGHEST YEAR OF SCHOOL COMPLETED

Coefficientsa

Model

Unstandardized Coefficients

Standardized Coefficients

t

Sig.

B

Std. Error

Beta

1 (Constant)

23.704

.195

121.831

.000

HIGHEST YEAR OF SCHOOL COMPLETED

.239

.011

.162

21.234

.000

RESPONDENTS SEX

-2.537

.073

-.263

-34.780

.000

SEX BEFORE MARRIAGE

-.191

.029

-.051

-6.595

.000

a. Dependent Variable: AGE WHEN FIRST MARRIED

a) Put into words what R2 is telling us.

b) Which of the three independent variables is the best predictor? How can you tell?

c) How would you report (or tweet!) your findings to a general audience?

gm_regression

Answers

2. Regression results

a) Almost 10% (9.6% exactly) of the variation in why people marry at different ages can be explained by these  independent variables.

b) All three are good predictors (the Betas are all statistically significant), but respondents’ sex is the strongest. It has the highest Beta at -.263 (remember: a minus sign does not make it less strong), and attitudes about sex before marriage is the weakest.

c) The Beta weights suggest that those who score high on the sex measure (women) are more likely to get married at younger ages than men are. Those with more education get married at older ages, and a slight tendency for those who disapprove of premarital sex to marry at later ages. In tweet form: those who are less educated, anti-premarital sex, and are women tend to get married at younger ages.

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