With the first set of questions asked and answered about this dataset, let's move on to additional analyses.
This recipe will investigate the makes and models of automobiles and how they have changed over time:
- Let's look at how the makes and models of cars inform fuel efficiency over time. First, let's look at the frequency of the makes and models of cars available in the US over this time and concentrate on four-cylinder cars:
carsMake <- ddply(gasCars4, ~year, summarise, numberOfMakes = length(unique(make))) ggplot(carsMake, aes(year, numberOfMakes)) + geom_point() + labs(x = "Year", y = "Number of available makes") + ggtitle("Four cylinder cars")
We see in the following graph that there has been a decline in the number of makes available over this period, though there has been a small uptick in recent times.
- Can we look...