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# PUBLG100: Introduction to Quantitative Methods
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# Week 3 Solutions: T-test for Difference in Means and Hypothesis Testing
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#

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library(foreign)
library(dplyr)
df <- read.dta("QoG2012.dta")
df <- rename(df, pol.stability = wbgi_pse)

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df$former_col <- factor(df$former_col, labels = c("not ex colony", "ex colony"))
t.test(df$pol.stability ~ df$former_col, mu=0, alt="two.sided", conf=0.95)

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t.test(df$pol.stability ~ df$former_col, mu=0, alt="two.sided", conf=0.99)

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t.test(df$pol.stability ~ df$former_col, mu=0.3, alt="two.sided", conf=0.99)

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df <- rename(df, latitude = lp_lat_abst)

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plot(df$latitude, df$pol.stability)

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cor.test(df$latitude, df$pol.stability, use="complete.obs", conf.level = 0.99)