Early childhood intervention study

Description

Cognitive scores of infants in a study of early childhood intervention. The 103 infants from low income African American families were divided into a treatment group (58 infants) and a control group (45 infants). Starting at 0.5 years of age the infants in the treatment group were exposed to an enriched environment. Each infant's cognitive score on an age-specific, normalized scale was recorded at ages 1, 1.5, and 2 years.

Usage

data(Early)

Format

This groupedData object contains the following columns

id

An ordered factor of the id number for each infant.

cog

A numeric cognitive score.

age

The age of the infant at the measurement.

trt

A factor with two levels, "N" and "Y", indicating if the infant is in the early childhood intervention program.

References

Singer, Judith D. and Willett, John B. (2003), Applied Longitudinal Data Analysis, Oxford University Press. (Ch. 3)

Examples

str(Early)