Linear mixed effect model- Birth rates data

Hierarchical and Mixed Effects Models in R

Richard Erickson

Data Scientist

Chapter outline

• Random-effect intercept model
• Random-effect slope model

Birth rates data

• Small populations subject to stochasticity
• Random-effects one solution to this problem
• Birth rates one such variable

How does a mothers age impact birth rate?

• Does a mother's age impact birth rate?
• Marketing and policy implications

lmer syntax in R

library(lme4)
lmer(y ~ x + (Random-effect), data = my_data)

Random-effect syntax

• (1 | group): Random intercept with fixed mean
• (1 | g1/g2): Intercepts vary among g1 and g2 within g1
• (1 | g1) + (1 | g2): Random intercepts for 2 variables
• x + (x | g): Correlated random slope and intercept
• x + (x || g): Uncorrelated random slope and intercept
• See lme4 for additional details

Let's practice!

Hierarchical and Mixed Effects Models in R