Stats Homework ( R)

1. Stats Homework (R) • help(swiss) • Fertility • ‘common standardized fertility measure’ • Examination • % draftees receiving highest mark on army examination • Education • % education beyond primary school for draftees. • Catholic • % ‘catholic’ (as opposed to ‘protestant’) • Is there a relationship between education and fertility? • Draw appropriate conclusions • Provide appropriate evidence (plots, stats) • Is there a relationship between education and examination? • Is the relationship the same for Catholic and Protestant provinces? • Provide appropriate evidence (plots, stats)

3. http://www.nytimes.com/2009/01/07/technology/business-computing/07program.htmlhttp://www.nytimes.com/2009/01/07/technology/business-computing/07program.html

4. Plot Example • help(ldeaths) • plot(mdeaths, col="blue", ylab="Deaths", sub="Male (blue), Female (pink)", ylim=range(c(mdeaths, fdeaths))) • lines(fdeaths, lwd=3, col="pink") • abline(v=1970:1980, lty=3) • abline(h=seq(0,3000,1000), lty=3, col="red")

5. Periodicity • plot(1:length(fdeaths), fdeaths, type='l') • lines((1:length(fdeaths))+12, fdeaths, lty=3)

6. Type Argument par(mfrow=c(2,2)) plot(fdeaths, type='p', main="points") plot(fdeaths, type='l', main="lines") plot(fdeaths, type='b', main="b") plot(fdeaths, type='o', main="o")

7. ScatterPlot • plot(as.vector(mdeaths), as.vector(fdeaths)) • g=glm(fdeaths ~ mdeaths) • abline(g) • g$coef (Intercept) mdeaths -45.2598005 0.4050554

8. Hist & Density • par(mfrow=c(2,1)) • hist(fdeaths/mdeaths, nclass=30) • plot(density(fdeaths/mdeaths))

9. Data Frames • help(cars) • names(cars) • summary(cars) • plot(cars) • cars2 = cars • cars2$speed2 = cars$speed^2 • cars2$speed3 = cars$speed^3 • summary(cars2) • names(cars2) • plot(cars2) • options(digits=2) • cor(cars2)

10. Normality par(mfrow=c(2,1)) plot(density(cars$dist/cars$speed)) lines(density(rnorm(1000000, mean(cars$dist/cars$speed), sqrt(var(cars$dist/ cars$speed)))), col="red") qqnorm(cars$dist/cars$speed) abline(mean(cars$dist/cars$speed), sqrt(var(cars$dist/cars$speed)))

11. Stopping Distance Increases Quickly With Speed • plot(cars$speed, cars$dist/cars$speed) • boxplot(split(cars$dist/cars$speed, round(cars$speed/10)*10))

12. Quadratic Model of Stopping Distance plot(cars$speed, cars$dist) cars$speed2 = cars$speed^2 g2 = glm(cars$dist ~ cars$speed2) lines(cars$speed, g2$fitted.values)

13. Bowed Residuals g1 = glm(dist ~ poly(speed, 1), data=cars) g2 = glm(dist ~ poly(speed, 2), data=cars) par(mfrow=c(1,2)) boxplot(split(g1$resid, round(cars$speed/5))); abline(h=0) boxplot(split(g2$resid, round(cars$speed/5))); abline(h=0)

14. Help, Demo, Example • demo(graphics) • example(plot) • example(lines) • help(cars) • help(WWWusage) • example(abline) • example(text) • example(par) • boxplots • example(boxplot) • help(chickwts) • demo(plotmath) • pairs • example(pairs) • help(quakes) • help(airquality) • help(attitude) • Anorexia • utils::data(anorexia, package="MASS") • pairs(anorexia, col=c("red", "green", "blue")[anorexia$Treat]) • counting • example(table) • example(quantile) • example(hist) • help(faithful)

15. Randomness • example(rnorm) • example(rbinom) • example(rt) • Normality • example(qqnorm) • Regression • help(cars) • example(glm) • demo(lm.glm)