Data: present

To access the data in R, type

source("http://www.openintro.org/stat/data/present.R")

Description

Number of male and female births, sex ratio at birth, and number of excess males: United States, 1940–2002. Source: Mathews TJ, and Hamilton BE. 2005. Trend analysis of the sex ratio at birth in the United States. National Vital Statistics Reports 53(20):1-17.

Format

A data frame with 63 observations on the following 3 variables.

• year: a numeric vector, 1940-2002
• boys: a numeric vector, number of male births
• girls: a numeric vector, number of female births