required packages

library(ggplot2)

source

source("more/present.R")
source("more/arbuthnot.R")

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?

Years

present$year
##  [1] 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953
## [15] 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967
## [29] 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981
## [43] 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
## [57] 1996 1997 1998 1999 2000 2001 2002

dimensions

dim(present)
## [1] 63  3

column names

names(present)
## [1] "year"  "boys"  "girls"

2.How do these counts compare to Arbuthnot’s? Are they on a similar scale?

arbuthnot’s Years

arbuthnot$year
##  [1] 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642
## [15] 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656
## [29] 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670
## [43] 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684
## [57] 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698
## [71] 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710
#Arbuthnot's data were taken between 1629 to 1710, where as the present data were taken between 1940 to 2002

arbuthnot’s dimensions

dim(arbuthnot)
## [1] 82  3
#Arbuthnot's data is 19 years longer then present data

present total

present$boys + present$girls
##  [1] 2360399 2513427 2808996 2936860 2794800 2735456 3288672 3699940
##  [9] 3535068 3559529 3554149 3750850 3846986 3902120 4017362 4047295
## [17] 4163090 4254784 4203812 4244796 4257850 4268326 4167362 4098020
## [25] 4027490 3760358 3606274 3520959 3501564 3600206 3731386 3555970
## [33] 3258411 3136965 3159958 3144198 3167788 3326632 3333279 3494398
## [41] 3612258 3629238 3680537 3638933 3669141 3760561 3756547 3809394
## [49] 3909510 4040958 4158212 4110907 4065014 4000240 3952767 3899589
## [57] 3891494 3880894 3941553 3959417 4058814 4025933 4021726

arbuthnot’s total

arbuthnot$boys + arbuthnot$girls
##  [1]  9901  9315  8524  9584  9997  9855 10034  9522  9160 10311 10150
## [12] 10850 10670 10370  9410  8104  7966  7163  7332  6544  5825  5612
## [23]  6071  6128  6155  6620  7004  7050  6685  6170  5990  6971  8855
## [34] 10019 10292 11722  9972  8997 10938 11633 12335 11997 12510 12563
## [45] 11895 11851 11775 12399 12626 12601 12288 12847 13355 13653 14735
## [56] 14702 14730 14694 14951 14588 14771 15211 15054 14918 15159 13632
## [67] 13976 14861 15829 16052 15363 14639 15616 15687 15448 11851 16145
## [78] 15369 16066 15862 15220 14928
#The count per year is much lager in present data, they are not similer in scale

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.

plot displaying boy-to-girl ratio

ratio <- present$boys/present$girls
ggplot(present, aes(x = year, y = ratio))+ geom_point(colour="red", size = 1)

#The boy to girl ratio declines over the sample years

Arbuthnot’s observation

present$boys > present$girls
##  [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
## [15] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
## [29] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
## [43] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
## [57] TRUE TRUE TRUE TRUE TRUE TRUE TRUE
#Arbuthnot's observation about boys being born in greater proportion than girls hold up in the U.S.

4.In what year did we see the most total number of births in the U.S.?

year with most total number of births

present$year[which.max(present$boys + present$girls)]
## [1] 1961