{r, fig.align = 'center'}
#| echo: false
#| message: false
# Create groups of 20 years starting from 1860-79
vdem <- vdem |>
mutate(period = cut(year, breaks = seq(1859, max(year), by = 20), labels = FALSE))
# Perform linear regression for each period
regression_results <- vdem |>
group_by(period) |>
summarise(
coefficient = coef(lm(e_migdppcln ~ v2x_polyarchy))[2],
period_start = min(year),
period_end = max(year)
)
# Filter out rows with period as "NA"
regression_results <- regression_results %>%
filter(!is.na(period))
# Print the filtered results
print(regression_results)