---
title: "Untitled"
output: word_document
date: "2025-07-02"
---
```{r}
# Load libraries
library(gapminder)
library(dplyr)
library(ggplot2)
library(car)  # for leveneTest

# Filter data for year 2007 and continents Europe and Asia
data_2007 <- gapminder %>%
  filter(year == 2007, continent %in% c("Europe", "Asia"))

# Check sample size by continent
table(data_2007$continent)

# Shapiro-Wilk test for normality by continent
by(data_2007$lifeExp, data_2007$continent, shapiro.test)

# Visual normality check
hist(data_2007$lifeExp, main = "Histogram of Life Expectancy (2007)", xlab = "Life Expectancy")
qqnorm(data_2007$lifeExp); qqline(data_2007$lifeExp)

# Levene's Test for homogeneity of variance
leveneTest(lifeExp ~ continent, data = data_2007)

# Boxplot
ggplot(data_2007, aes(x = continent, y = lifeExp)) +
  geom_boxplot() +
  theme_minimal() +
  labs(title = "Life Expectancy by Continent (2007)")

# T-test
t.test(lifeExp ~ continent, data = data_2007, var.equal = FALSE)

```

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