Describing Variables & Hypotheses Testing May 26, 2008 Ivan Katchanovski, Ph.D. POL 242Y-Y

Research Hypothesis Hypothesis: A basic statement that is tested in research – Based on a political science theory and previous research – States expected relationship between dependent and independent variables – This relationship can be tested with empirical data – Hypothesis is either supported or not supported by research 2

Dependent and independent variables Dependent variable A variable assumed to depend on or be affected by the independent variable A variable which we are interested in explaining – Income level depends on education level – The level of democracy is affected the level of economic development Independent variabl e A variable which presumed to affect the dependent variable A variable which we use to explain the dependent variable – Education level increases personal income – The level of economic development has a positive effect on the odds that a country is democratic 3

Examples of Research Hypotheses People with higher income are more likely to vote for the Conservative Party – Pocket book theory of voting behaviour Americans are more likely to join civic associations than Canadians are – Political culture theory Democratic countries do not wage wars with other democratic countries – Democratic peace theory 4

Exercise 5 Formulate a hypothesis describing relationship between political views and religiosity. Identify the dependent variable and the independent variable.

Outline of Research Paper Political science theory previous research Your research hypothesis Data One of datasets from POL 242Y Research Method 6

Quantitative Analysis Univariate - describe a case in terms of a single variable. – Frequency distribution tables and charts Bivariate - describe a case in terms of two variables simultaneously. Multivariate - analysis of two or more variables simultaneously. 7

Frequency distributions Tables or charts that summarize the distribution of a variable Economic development level (World dataset) 8 FrequencyPercent Cumulative Percent Least Middle Most Total

Collapsing categories ResponsePercent Very good5 Good42 Poor21 Very poor6 Don’t Know26 Total, percent100 9 ResponsePercent Good or better 64 Poor or worse 36 Total, percent100 Table 1a. How is the government doing in solving the budget crisis? Table 1b. Evaluation of government performance in solving the budget crisis?

Graphic description of variables Pie chartBar chart 10

11 Graphic description of variables Histogram Figure1. Age distribution of respondents Line chart

12 Measures Of Central Tendency The Mode: Value that occurs most frequently – useful for nominal variables The Median: middle value – useful for ordinal and interval-ratio variables Other Measures of Position: – Percentiles, deciles and quartiles _ The Mean: average score X=  (X i )/N – useful for interval-ratio variables

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14 Skewed Distributions Skew: The extent to which a distribution of scores has a few scores that are extremely high or extremely low. Positively skewed distribution Unskewed distribution