Line Graphs - R Graphics - page 91

1900 5 - 14 16966

1900 15 - 24 14951

1900 25 - 34 12161

1900 35 - 44 9273

1900 45 - 54 6437

1900 55 - 64 4026

1900 > 64 3099

1901 < 5 9336

1901 5 - 14 17158

...

We'll use ddply() to split it into separate data frames for each value of Year , then apply the
transform() function to each piece and calculate the Percent for each piece. Then ddply()
puts all the data frames back together:

uspopage_prop <- ddply(uspopage, "Year" , transform,
Percent = Thousands / sum(Thousands) * 100 )

Year AgeGroup Thousands Percent
1900

< 5 9181 12.065340

1900 5 - 14 16966 22.296107

1900 15 - 24 14951 19.648067

1900 25 - 34 12161 15.981549

1900 35 - 44 9273 12.186243

1900 45 - 54 6437 8.459274

1900 55 - 64 4026 5.290825

1900 > 64 3099 4.072594

1901 < 5 9336 12.033409

1901 5 - 14 17158 22.115385

...

See Also
For more on summarizing data by groups, see Summarizing Data by Groups .

Adding a Confidence Region

Problem
You want to add a confidence region to a graph.

Solution
Use geom_ribbon() and map values to ymin and ymax .