Independent Sample T-test

1. Independent Sample T-test • Classical design used in psychology/medicine • N subjects are randomly assigned to two groups (Control * Treatment). • After treatment, the individuals are measured on the dependent variable. • A test of differences in means between groups provides evidence for the treatment's effect.

2. Measures of Variation • A lot of statistical techniques (using interval data) use measures of variation in some manner • What is the difference between a standard deviation, the standard error of the mean, and the standard error of the difference between means? Or How are they related? Look in the glossary to help you answer these questions?

3. Using Measures of Variation • Leaned how to measure variation in data, i.e., variance, standard deviation (Ch.4) • Used the normal curve & SD to calculate z-scores and probabilities (Ch.5) • Used the normal curve & the z-score & the SE of the mean to calculate confidence intervals (Ch.6) • Used the concept of the confidence interval and the standard error of the differences between means to calculate the t-test (Ch.7) • Use the sum of squares Σ(X – Mean)2 [sum of the squared differences from the mean] in ANOVA

4. Null Hypothesis • The two groups come from the same population or that the two means are equal • μ1 = μ2

5. Levels of Significance • What does an α = .05 level of significance mean? • We decide to reject the null if the probability is very small (5% or less) that the sample difference is a product of sampling error. • The observed difference is outside the 95% confidence interval of the difference

6. Choosing a Level of Significance • Convention • Minimize type I error – Reject null hypothesis when the null is true • Minimize type II error – fail to reject null when the null is false • Making alpha smaller reduces the likelihood of making a type I error • Making alpha larger reduces the probability of a type II error

7. Independent Sample T-test Formula t =

8. Assumptions of the t-test • 1. All observations must be independent of each other (random sample should do this) • 2. The dependent variable must be measured on an interval or ratio scale • 3. The dependent variable must be normally distributed in the population (for each group being compared). (NORMALITY ASSUMPTION) [this usually occurs when N is large and randomly selected] • 4. The distribution of the dependent variable for one of the groups being compared must have the same variance as the distribution for the other group being compared. (HOMOGENEITY OF VARIANCE ASSUMPTION)

9. Don’t worry about these assumptions to much, but • Point 1: statistical tools are attempting to quantify and analyze very complex social/political phenomenon • Point 2: For these test to be accurate they relay on simplifying the world with many assumptions that might not be true • Point 3: social science researchers violate these assumptions quite often, but try to be honest about it • Point 4: there are sometimes ways of testing and adjusting for violations

11. SPSS & the Independent Sample T-Test

12. Crime and Support for Democracy Kenneth E. Fernandez Department of Political Science University of Nevada, Las Vegas Michele Kuenzi Department of Political Science University of Nevada, Las Vegas

13. Research Question Does crime influence how citizens evaluate democracies or influence their level of support for democracy?

14. Why is this an Interesting Question? • Scholars have noted that few studies, especially in the field of political science, have examined crime and its impact on society in a comparative manner (Beirne 1997; Howard, et al. 2000). • Current public opinion research suggests that the issue of crime is of great concern to citizens across the globe (Quann and Hung 2002) • Many countries that have experienced recent democratic reforms have also experienced increasing crime rates (Bergman 2006).

15. What theories inform the study of crime and democracy? • Social Capital • Rational Choice • Modernization Theory

16. Social Capital Theories: • Theory suggests that attitudes and feelings of the masses regarding obligations within a group, civic attachments, trust, and efficacy are important determinants of democratic transition and sustainability (Muller and Seligson 1994). • Yet crime and violence is likely to reduce trust and social capital (Lederman et al 2002).

17. Rational Choice: • Citizens are treated as utility maximizing consumers • A political regime is expected to produce some value or benefit to the consumer (Lane 1995). • Regime support depends on how well citizens’ demands are met • Thomas Hobbes argues that protection against violence is the highest and most fundamental human need and a citizen of the state has a right to revoke its support and loyalty when the state proves incapable of protecting its subjects.

18. The Paradox of Modernization theory: • Modernization leads to increasing wealth, leading to more literacy, education, urbanization, leading to democratization because citizens are less willing to put up with oppressive, authoritarian behavior and more willing to support democracy (Lipset 1959) • But modernization may cause a breakdown in traditional structures and values, an increase in interaction, tension, and conflict. These social changes then contribute to rising criminal activity (Heiland and Shelley 1992).

19. Modernization Theory, Crime & Democracy • Consolidating both the political science and the criminology/sociology literature on modernization theory, we argue that socio-economic conditions, as well as, crime and publicsafety influence citizens’ support for democracy.

20. Crime is Often Ignored as a Factor in Democratization • Much of the prior research on the development of democracy focuses on economic conditions (Arat 1988; Epstein et al. 2006; Lipset 1959; Przeworski et al. 2000). • In fact, Kugler and Feng describe the recent application of modernization theory as positing that “economic development is a sufficient, rather than a necessary, condition for democratic transitions” (1999, 140). • We argue that crime and public disorder may pose even greater challenges to the legitimacy and effectiveness of democratic institutions

21. Methodology: Macro or Micro Level Analysis? • Much of the research testing the modernization theory uses a macrolevel approach utilizing the nation-state at time t as the unit of analysis. Aggregate national characteristics (i.e., per capita GDP) are then used as predictors of some measure of democracy. • Yet Lipset (1959) posits that increases in wealth and income leads to democratic transition because it affects citizens’ values. • We would like to examine this microlevel statement.

22. Microlevel Analysis: • An examination of citizen attitudes is appropriate because the success of democratic consolidation in these emerging democracies is often linked to citizens’ support for democracy and perceptions of government performance (Hiskey and Bowler 2005; Lagos 2001; Diamond 1999; Lipset 1959).

23. DATA: • Afrobarometer (AB) and Latinbarometro (LB) Survey Data • The AB and LB together contain 33 countries (16 in Africa and 17 in Latin America). Two Statistical Approaches • Analysis of all countries pooled together (over 18,000 respondents in African and 13,000 in Latin America • Analysis of 4 cases

24. Case Selection: • Initial Case - NIGERIA: Like many other African countries, Nigeria experienced a transition to democracy in the 1990s. We chose Nigeria because crime is a very salient issue in this country, and Nigeria has been well known for mob justice or what has been called “jungle justice” • Most Different Systems Design: We performed a cluster analysis to find a case in the Afrobarometer data that was “most different” to Nigeria in relation to three factors: crime, democracy and per capita GDP.

25. Cluster Analysis: The Euclidean distance between two cases is calculated by finding the square root of the sum of the squared differences between the two cases for each of the three variables (crime rate; per capita GDP; level of democracy):

26. MALAWI: Nigeria has a per capita GDP nearly 3 times that of Malawi, but Nigeria has a substantially higher reported victimization rate (Nigeria had the highest reported attacks of the 14 African cases and Malawi had the lowest). Both countries were given a score of 4 for political rights and civil liberties by Freedom House in 2005. CHILE & NICARAGUA:Both Chile and Nicaragua have modest crime rates compared to the rest of Central and South America, but differ greatly on GDP and level of democracy. Chile has a per capita GDP almost 7 times higher than Nicaragua and Chile has a score of 1 for both political rights and civil liberties while Nicaragua scored a 3 for both.

27. THE 4 CASES: The results seem to make intuitive sense. There is substantial variation in GDP across cases, they vary in crime rates from low to moderate to high levels of victimization, and levels of political freedom and civil liberties varied from the highest (score of 1) to moderate/low (score of 4).

28. Operationalization Dependent Variables: Attitudes toward Democracy Support for Democracy • Which of these three statements is closest to your own opinion? • A: Democracy is preferable to any other kind of government. • B: In some circumstances, a non-democratic government can be preferable. • C: For someone like me, it doesn’t matter what kind of government we have. • Recoded so that the value on this variable is 1 if the response was A, and 0 otherwise.

29. Satisfaction with Democracy • Overall, how satisfied are you with the way democracy works in __________.? Are you: • 0=Tanzania/Nigeria is not a democracy, 1=Not at all satisfied, 2=Not very satisfied, 3=Fairly satisfied, 4=Very satisfied. Chile and Nicaragua: • In general, would you say that you are very satisfied, fairly satisfied, not very satisfied or not at all satisfied with the way democracy works in (country)? 4=Very satisfied - 1=Not at all satisfied

30. Independent Variables • Experience with Crime • Comparative assessments of safety from crime and violence • Crime Performance

31. Control Variables • Demographic variables: gender, level of poverty, age, education • Other variables: political engagement, identification with the party in power, and subjective assessments of satisfaction with life and the economy and government service delivery

38. Results Attitudes toward Democracy Feeling Safe • Nigerians who report feeling better off in terms of safety from crime and violence are significantly more likely to: • Support democracy • Be satisfied with the way democracy is working

39. Malawians who report feeling better off in terms of safety from crime and violence are significantly more likely to: • Be satisfied with the way democracy is working

40. Nicaraguans and Chileans who felt the country was getting safer were also more likely to: • Support democracy • Be satisfied with the way democracy is working

41. Government Performance in Crime Reduction • Results generally stronger

42. Crime Victimization • Nigerians and Malawians who report a higher number of experiences with crime victimization have significantly lower levels of support for democracy. • There appears to be no relationship between crime victimization and attitudes toward democracy in the Chile and Nicaragua countries.

43. Conclusion and Implications • Perceptions of safety and government performance in the area of crime affect attitudes toward democracy. • Crime victimization generally does not appear related to satisfaction with democracy.

44. Issue of crime likely to affect the consolidation of democracy

45. Future research should: • Examine other regions • Assess whether there is a threshold effect • Examine potential intervening variables