0. Read in data first.
1. What years are included in this data set? What are the dimensions of the data frame and what are the variable or column names? 1.0
source(“http://www.openintro.org/stat/data/present.R”) present
dim(present) [1] 63 3
names(present) [1] “year” “boys” “girls”
( The year range is from 1940 - 202 , The outputted dimensions give the following output : [1] , 63 - rows and 3 columns and columns names being “year” , “boys” , ” girls”)
2. How do these counts compare to Arbuthnot’s? Are they on a similar scale? 1.0 pt
dim(present) [1] 63 3
names(present) [1] “year” “boys” “girls”
(The dimensions indicate both having 3 rows but different row counts and similar headers. )
3. Make a plot that displays the boy-to-girl ratio for every year in the data set. What do you see? Does Arbuthnot’s observation about boys being born in greater proportion than girls hold up in the U.S.? Include the plot in your response. 2.0 pts
plot(present\(year, present\)boys / present$girls, type = “l”)
(The ratio shows values greater than 1 from 1940 to 2000 in the ration axis (y) and supports Arbuthnot’s observation.)
4. In what year did we see the most total number of births in the U.S.? You can refer to the help files or the R reference card http://cran.r-project.org/doc/contrib/Short-refcard.pdf to find helpful commands. 1.0pt
plot(present\(year, present\)boys + present$girls, type = “l”)
(1961 shows the highest total number of births from estimating from the output plot.)