library(MASS) Boston$old <- as.numeric(Boston$age >= 95) # realizar la regresión y asígnar el resultado a mod_bc. # extraer los coeficientes estimados del modelo y asignar el resultado a params. # graficar medv contra indus y agregar las líneas de regresión. # realizar la regresión y asígnar el resultado a mod_bc. mod_bc <- lm(medv ~ indus*old, data = Boston) # extraer los coeficientes estimados del modelo y asignar el resultado a params. params <- coef(mod_bc) # graficar medv contra indus y agregar las líneas de regresión. plot(medv ~ indus, data = Boston) abline(a = params[1], b = params[2], col = "red") abline(a = params[1] + params[3], b = params[2] + params[4], col = "darkblue") test_or({ test_object("mod_bc") },{ f <- ex() %>% override_solution("lm(medv ~ old*indus, data = Boston)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("lm(Boston$medv ~ Boston$indus*Boston$old)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("lm(Boston$medv ~ Boston$old*Boston$indus)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("attach(Boston);lm(medv ~ indus*old)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("attach(Boston);lm(medv ~ old*indus)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("lm(medv ~ indus + old + indus:old, data = Boston)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("lm(medv ~ old + indus + old:indus, data = Boston)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("lm(Boston$medv ~ Boston$indus + Boston$old + Boston$indus:Boston$old)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("lm(Boston$medv ~ Boston$old + Boston$indus + Boston$old:Boston$indus)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("attach(Boston);lm(medv ~ indus + old + indus:old)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() },{ f <- ex() %>% override_solution("attach(Boston);lm(medv ~ old + indus + old:indus)") %>% check_function("lm") f %>% check_arg("formula") %>% check_equal() }) ex() %>% check_object("params") %>% check_equal() test_or({ ex() %>% check_function("plot") %>% { check_arg(., "formula") %>% check_equal() check_arg(., "data") %>% check_equal() }},{ f <- ex() %>% override_solution("plot(Boston$indus, Boston$medv)") %>% check_function("plot") f %>% { check_arg(., "x") %>% check_equal() check_arg(., "y") %>% check_equal() }},{ f <- ex() %>% override_solution("plot(Boston$medv ~ Boston$indus)") %>% check_function("plot") f %>% check_arg("formula") %>% check_equal() }) test_or({ ex() %>% check_function("abline", index = 1) %>% { check_arg(., "a") %>% check_equal() check_arg(., "b") %>% check_equal() } ex() %>% check_function("abline", index = 2) %>% { check_arg(., "a") %>% check_equal() check_arg(., "b") %>% check_equal() }},{ f <- ex() %>% override_solution("abline(a = params[1], b = params[2]);abline(coef = c(params[1] + params[3], params[2] + params[4]))") f %>% check_function("abline", index = 1) %>% { check_arg(., "a") %>% check_equal() check_arg(., "b") %>% check_equal() } f %>% check_function("abline", index = 2) %>% check_arg("coef") %>% check_equal() },{ f <- ex() %>% override_solution("abline(coef = c(params[1], params[2]));abline(coef = c(params[1] + params[3], params[2] + params[4]))") f %>% check_function("abline", index = 1) %>% check_arg("coef") %>% check_equal() f %>% check_function("abline", index = 2) %>% check_arg("coef") %>% check_equal() },{ f <- ex() %>% override_solution("abline(coef = c(params[1], params[2]));abline(a = params[1] + params[3], b = params[2] + params[4])") f %>% check_function("abline", index = 1) %>% check_arg("coef") %>% check_equal() f %>% check_function("abline", index = 2) %>% { check_arg(., "a") %>% check_equal() check_arg(., "b") %>% check_equal() }}) success_msg("¡Correcto! Se puede ver que la disminución en el valor medio de la vivienda debido a un aumento en la proporción de edificios industriales es, en términos absolutos, menor en los suburbios donde la proporción de edificios antiguos es alta.")