1. 1 SOC 3811 Basic Social Statistics

2. 2 Class overview Compare means of two groups  Assignment 4 correction  Concept review  Two sample t-test: different cases  Assignment 5

3. 3 Simple regression model

4. 4 Interpretation  Education has a positive influence on the respondent ’ s age when his/her first child was born.  the slop = 0.61  For each additional year of schooling, it delays when the respondent had his/her first child born by 0.61 year (about 7.3 months).

5. 5 Multiple Regression Model

6. 6 Interpretation  Education and Professional type both have positive influence on the age when the respondent ’ s first child was born.  the slop for Educ = 0.495  the slop for PROF =1.360  Controlling for professional type, every additional year of schooling delays when the respondent ’ s first child was born by 0.50 year (about 6 months).  Controlling for education, being in a managerial position delays when the respondent ’ s first child was born by 1.36 year (about 1 year and 4months).

7. 7 Multiple Regression Model with Interaction term

8. 8 Interpretation  No interaction effect based on this data.  Being in a managerial position does not mediate the influence of education on the respondent ’ s age when the first child was born.

9. 9 Independent samples T-test

10. 10 F-test  H o : variances are equal  H a : variances are not equal  If Sig. (p value)>.05 → can ’ t reject H o (variances are equal)  If Sig. (p value)≤.05 → reject H o (variances are not equal)

11. 11 T-test Ho:Ho: H a :  Calculating z/t score: (note: the formula of is different for cases)

12. 12  Calculating z/t :  For any two means, the difference will also fall in a certain range. We can guess the range in which it typically falls  one-tail test two-tail test   -1.645 -1.961.96

13. 13 Dependent samples T test

14. 14 95% Confidence Interval  If 95% C.I. captures the null value (0) → can ’ t reject the null hypothesis  If 95% C.I. doesn ’ t capture the null value (0) → reject the null hypothesis

15. 15 Example 1

16. 16 Example 1

17. 17 Example 1

18. 18 Independent samples Unequal variance 

19. 19 Example 2

20. 20 Example 2

21. 21 Example 2

22. 22 Independent samples / Equal variances

23. 23 Example 3

24. 24 Example 3

25. 25 Dependent samples

26. 26  Assignment 5 – due next lab  Occupation, Industry are not continuous variables!!  Notice how the values ordered!  Don ’ t forget to pick up your assignment.