Question

I have the data in two files. I want to plot a graph the ratio of their frequencies.

For example, in my file A numbers from 1 to 5 occurs 20 times. In my file B, numbers from 1 to 5 occurs 10 times(histogram has bar width of 5). The ratio of those two is 20/10 = 2. I want to plot this ratio in a graph. Can it be done using R?

Answer 1

Assuming you read the 2 files in the variables data1 and data2 you could do:

bins <- seq(0, 100, 5) # Change this to whatever range your data encopasses
h1 <- hist(data1, bins, plot=0)
h2 <- hist(data2, bins, plot=0)

ratio <- h1$counts/h2$counts
# Remove NaNs and Infs due to 0 counts
ratio[is.na(ratio)] <- 0
ratio[is.inf(ratio)] <- 0
barplot(ratio)

Alternatively you can create a 3rd hist object, which has the advantage of correctly plotting the x-axis

h3 <- h1
h3$counts <- ratio
plot(h3, col="black")