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###                        Problem 5.10                       ###
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##--- Enter data
x <- c(1935, 1940, 1945, 1950, 1955, 1960, 1965, 1970, 1975,1980)
y <- c(32.1, 30.5, 24.4, 23.0, 19.1, 15.6, 12.4, 9.7, 8.9,7.2)

##--- Scatterplot
plot(x, y)

##--- Fit the least-squares regression line to data
model <- lm(y ~ x)
summary(model)

##--- Put the regression line on the scatterplot
abline(model)

##--- Calculate residuals
residuals(model)

##--- Residual plot
plot(x, residuals(model))
abline(h=0)


##--- Some elementary statistics
#--Mean
mean(x)
mean(y)

#--Standard deviation
sd(x)
sd(y)

#--Median
median(x)
median(y)

#--Correlation
cor(x, y)

#--Stem plot
stem(x)
stem(y)

#--Histogram
hist(x)
hist(y)

#--Pie chart
pie(x)
pie(y)