stat545a-2013-hw02
This is an R Markdown document for practicing basic syntax, with the dataset of gapminderDataFiveYear.txt. It will include the following steps:
The data is imported from an URL.
## data import from URL
gdURL <- "http://www.stat.ubc.ca/~jenny/notOcto/STAT545A/examples/gapminder/data/gapminderDataFiveYear.txt"
gDat <- read.delim(file = gdURL)
The function str() is used to get sense of the structure of the dataset.
str(gDat)
## 'data.frame': 1704 obs. of 6 variables:
## $ country : Factor w/ 142 levels "Afghanistan",..: 1 1 1 1 1 1 1 1 1 1 ...
## $ year : int 1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 ...
## $ pop : num 8425333 9240934 10267083 11537966 13079460 ...
## $ continent: Factor w/ 5 levels "Africa","Americas",..: 3 3 3 3 3 3 3 3 3 3 ...
## $ lifeExp : num 28.8 30.3 32 34 36.1 ...
## $ gdpPercap: num 779 821 853 836 740 ...
And summmary() is employed to get a overview of the descriptive statistics.
summary(gDat)
## country year pop continent
## Afghanistan: 12 Min. :1952 Min. :6.00e+04 Africa :624
## Albania : 12 1st Qu.:1966 1st Qu.:2.79e+06 Americas:300
## Algeria : 12 Median :1980 Median :7.02e+06 Asia :396
## Angola : 12 Mean :1980 Mean :2.96e+07 Europe :360
## Argentina : 12 3rd Qu.:1993 3rd Qu.:1.96e+07 Oceania : 24
## Australia : 12 Max. :2007 Max. :1.32e+09
## (Other) :1632
## lifeExp gdpPercap
## Min. :23.6 Min. : 241
## 1st Qu.:48.2 1st Qu.: 1202
## Median :60.7 Median : 3532
## Mean :59.5 Mean : 7215
## 3rd Qu.:70.8 3rd Qu.: 9325
## Max. :82.6 Max. :113523
##
To explore the relationship between life expectancy and GDP/capital, the following xyplot is generated.
library(lattice)
xyplot(lifeExp ~ gdpPercap, gDat)
According to the output figure, it can be inferred that GDP/capital have affect on life expectancy positively when it is below certain level.
Note: How to configure the scale of the plot?
To further examine the hypotehsis, another plot that grouping the results based on continent.
xyplot(lifeExp ~ gdpPercap | continent, gDat, subset = year == 2007)
In the case of Africa whose GDP/capital is the lowest, it shows a positive relationship between GDP/capital and life expectancy. For other more developed economy, the relationship is not that significant.