Homework 3.3 32
Chapter 3, Displaying and Describing Catagorical Data
Homework 3.3 Problem 32
Obesity <- matrix(c(23.8,26,35.6,27.8,28.7,28.1,31.6,31.1,27.2,16.8,14.2,9.1),ncol=3,byrow=TRUE)
colnames(Obesity) <- c("Normal %","Overweight %","Obese %")
rownames(Obesity) <- c("Inactive","Irregularly active","Regular not intense","Regular intense")
Obesity <- as.table(Obesity)
Obesity## Normal % Overweight % Obese %
## Inactive 23.8 26.0 35.6
## Irregularly active 27.8 28.7 28.1
## Regular not intense 31.6 31.1 27.2
## Regular intense 16.8 14.2 9.1CrossTable from the gmodels package does all these at once.
library(gmodels)
as.data.frame.matrix(Obesity)## Normal % Overweight % Obese %
## Inactive 23.8 26.0 35.6
## Irregularly active 27.8 28.7 28.1
## Regular not intense 31.6 31.1 27.2
## Regular intense 16.8 14.2 9.1CrossTable(Obesity, prop.t=TRUE, prop.r=TRUE, prop.c=TRUE)##
##
## Cell Contents
## |-------------------------|
## | N |
## | Chi-square contribution |
## | N / Row Total |
## | N / Col Total |
## | N / Table Total |
## |-------------------------|
##
##
## Total Observations in Table: 300
##
##
## |
## | Normal % | Overweight % | Obese % | Row Total |
## --------------------|--------------|--------------|--------------|--------------|
## Inactive | 23 | 26 | 35 | 85 |
## | 0.765 | 0.214 | 1.788 | |
## | 0.279 | 0.304 | 0.417 | 0.285 |
## | 0.238 | 0.260 | 0.356 | |
## | 0.079 | 0.087 | 0.119 | |
## --------------------|--------------|--------------|--------------|--------------|
## Irregularly active | 27 | 28 | 28 | 84 |
## | 0.006 | 0.009 | 0.000 | |
## | 0.329 | 0.339 | 0.332 | 0.282 |
## | 0.278 | 0.287 | 0.281 | |
## | 0.093 | 0.096 | 0.094 | |
## --------------------|--------------|--------------|--------------|--------------|
## Regular not intense | 31 | 31 | 27 | 89 |
## | 0.089 | 0.043 | 0.255 | |
## | 0.352 | 0.346 | 0.303 | 0.300 |
## | 0.316 | 0.311 | 0.272 | |
## | 0.105 | 0.104 | 0.091 | |
## --------------------|--------------|--------------|--------------|--------------|
## Regular intense | 16 | 14 | 9 | 40 |
## | 0.882 | 0.052 | 1.362 | |
## | 0.419 | 0.354 | 0.227 | 0.134 |
## | 0.168 | 0.142 | 0.091 | |
## | 0.056 | 0.047 | 0.030 | |
## --------------------|--------------|--------------|--------------|--------------|
## Column Total | 100 | 100 | 100 | 300 |
## | 0.333 | 0.333 | 0.333 | |
## --------------------|--------------|--------------|--------------|--------------|
##
## - Column percentages
- below
- Yes, these studies show a clear correlation that the less you exersise, the more likely you are to be obese.
Some graphs…
Y axis is physical activity in the order from bottom to top since i couldn’t figure out how to add y axis labels!! A. Inactive B. Irregularly active C. Regular, not intense D. Regular, intense
barplot(Obesity, main = "Body mass index", xlab = "Physical activity", col=c("blue","green","yellow","magenta"))