Describing Variables & Hypotheses Testing May 26, 2008 Ivan Katchanovski, Ph.D. POL 242Y-Y
Jan 18, 2018
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
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Dependent and independent variablesDependent 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 variable
• 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
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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
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Exercise
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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
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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.
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Frequency distributions
Tables or charts that summarize the distribution of a variable
Economic development level (World dataset)
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Frequency PercentCumulative
Percent Least 22 20.8 20.8Middle 54 50.9 71.7Most 30 28.3 100.0Total 106 100.0
Collapsing categories
Response PercentVery good 5Good 42Poor 21Very poor 6Don’t Know 26Total, percent 100
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Response Percent
Good or better 64
Poor or worse 36
Total, percent 100
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 chart Bar chart
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Graphic description of variables
Histogram
Figure1. Age distribution of respondents
Line chart
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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=(Xi)/N – useful for interval-ratio variables
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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