EXERCISE 1.

a.What are the dimensions of the present data frame? [1] 63 3 b.What are the column names? [1] “year” “boys” “girls” c1.Display the years included in the data set. (Type present$year as a command and the data will be displayed when the code block is run.) [1] 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 [17] 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 [33] 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 [49] 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

c2. What years are included in this data set? 1940 to 2002

EXERCISE 2.

  1. Find the total number of births by year. year total 1 1940 2360399 2 1941 2513427 3 1942 2808996 4 1943 2936860 5 1944 2794800 6 1945 2735456 7 1946 3288672 8 1947 3699940 9 1948 3535068 10 1949 3559529 11 1950 3554149 12 1951 3750850 13 1952 3846986 14 1953 3902120 15 1954 4017362 16 1955 4047295 17 1956 4163090 18 1957 4254784 19 1958 4203812 20 1959 4244796 21 1960 4257850 22 1961 4268326 23 1962 4167362 24 1963 4098020 25 1964 4027490 26 1965 3760358 27 1966 3606274 28 1967 3520959 29 1968 3501564 30 1969 3600206 31 1970 3731386 32 1971 3555970 33 1972 3258411 34 1973 3136965 35 1974 3159958 36 1975 3144198 37 1976 3167788 38 1977 3326632 39 1978 3333279 40 1979 3494398 41 1980 3612258 42 1981 3629238 43 1982 3680537 44 1983 3638933 45 1984 3669141 46 1985 3760561 47 1986 3756547 48 1987 3809394 49 1988 3909510 50 1989 4040958 51 1990 4158212 52 1991 4110907 53 1992 4065014 54 1993 4000240 55 1994 3952767 56 1995 3899589 57 1996 3891494 58 1997 3880894 59 1998 3941553 60 1999 3959417 61 2000 4058814 62 2001 4025933 63 2002 4021726

  2. Plot the total number of births by year with year on the x axis.

  3. What observations do you make based on the plot? Births were increasing steadily until the 1970s when they dip down and don’t rise again until the mid 1980s.

EXERCISE 3.

  1. Make a plot that displays the boy-to-girl ratio for every year in the data set.

  2. What do you conclude based on the plot? Each year more boys are born in comparison to girls.

EXERCISE 4.

  1. What was the greatest number of births in the U.S. during the timeframe of the data? [1] 4268326

  2. In what year was the total number of births in the U.S. the greatest? [1] 1961