---
title: "Session 14 — Naive association"
author: "Prof. Dae-Jin Lee (daelee@faculty.ie.edu)"
date: "Fall 2026"
output:
  html_document:
    toc: true
    theme: flatly
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE, message = FALSE, warning = FALSE)
library(tidyverse)
```

```{r}
world <- read_csv("data/country_indicators.csv")

ggplot(world, aes(x = democracy_score, y = life_expectancy)) +
  geom_point() +
  geom_smooth(method = "lm", se = FALSE) +
  labs(
    title = "Association — not automatically causation",
    x = "Democracy score",
    y = "Life expectancy"
  )

m_naive <- lm(life_expectancy ~ democracy_score, data = world)
summary(m_naive)
```

**Interpret descriptively:** how life expectancy co-moves with democracy scores in this sample. Do **not** conclude that democracy causes longevity from this alone.