primer cuarto

# Cargar librerías necesarias
library(tidyverse)

── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
✔ dplyr     1.1.4     ✔ readr     2.1.5
✔ forcats   1.0.0     ✔ stringr   1.5.1
✔ ggplot2   3.5.2     ✔ tibble    3.2.1
✔ lubridate 1.9.4     ✔ tidyr     1.3.1
✔ purrr     1.0.4     
── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
✖ dplyr::filter() masks stats::filter()
✖ dplyr::lag()    masks stats::lag()
ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors

library(knitr)

# Vista general de la base de datos
head(iris)

  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa
3          4.7         3.2          1.3         0.2  setosa
4          4.6         3.1          1.5         0.2  setosa
5          5.0         3.6          1.4         0.2  setosa
6          5.4         3.9          1.7         0.4  setosa

# Resumen de variables numéricas por especie
iris %>%
  group_by(Species) %>%
  summarise(
    Sepal.Length.Mean = mean(Sepal.Length),
    Sepal.Width.Mean = mean(Sepal.Width),
    Petal.Length.Mean = mean(Petal.Length),
    Petal.Width.Mean = mean(Petal.Width),
    .groups = "drop"
  ) %>%
  kable()

Species	Sepal.Length.Mean	Sepal.Width.Mean	Petal.Length.Mean	Petal.Width.Mean
setosa	5.006	3.428	1.462	0.246
versicolor	5.936	2.770	4.260	1.326
virginica	6.588	2.974	5.552	2.026

# Gráfico de dispersión entre largo y ancho de pétalo
ggplot(iris, aes(x = Petal.Length, y = Petal.Width, color = Species)) +
  geom_point(size = 3, alpha = 0.7) +
  labs(
    title = "Relación entre largo y ancho del pétalo",
    x = "Largo del Pétalo",
    y = "Ancho del Pétalo"
  ) +
  theme_minimal()

# Modelo simple para predecir Sepal.Length
modelo <- lm(Sepal.Length ~ Petal.Length + Species, data = iris)
summary(modelo)

Call:
lm(formula = Sepal.Length ~ Petal.Length + Species, data = iris)

Residuals:
     Min       1Q   Median       3Q      Max 
-0.75310 -0.23142 -0.00081  0.23085  1.03100 

Coefficients:
                  Estimate Std. Error t value Pr(>|t|)    
(Intercept)        3.68353    0.10610  34.719  < 2e-16 ***
Petal.Length       0.90456    0.06479  13.962  < 2e-16 ***
Speciesversicolor -1.60097    0.19347  -8.275 7.37e-14 ***
Speciesvirginica  -2.11767    0.27346  -7.744 1.48e-12 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 0.338 on 146 degrees of freedom
Multiple R-squared:  0.8367,    Adjusted R-squared:  0.8334 
F-statistic: 249.4 on 3 and 146 DF,  p-value: < 2.2e-16