## ----echo = FALSE, message = FALSE------------------------------------------------------------------- library(tidyverse) library(scales) library(ISLR) library(knitr) theme_set(theme_bw()) ## ---------------------------------------------------------------------------------------------------- ## load the data in ads <- read_csv("data/Advertising.csv") ## fit the model model <- lm(sales ~ TV, data = ads) summary(model) ## ---- echo=FALSE------------------------------------------------------------------------------------- ggplot(aes(TV, sales), data = ads) + geom_point() + geom_smooth(method = "lm") ## ---------------------------------------------------------------------------------------------------- summary(model) ## ---------------------------------------------------------------------------------------------------- # model_2 <- lm(sales ~ TV + radio + newspaper, data = ads) model_2 <- lm(sales ~ ., data = ads[, -1]) summary(model_2) ## ---------------------------------------------------------------------------------------------------- # model with TV, radio, and newspaper summary(model_2) # model without newspaper summary(lm(sales ~ TV + radio, data = ads)) ## ---------------------------------------------------------------------------------------------------- ggplot() + geom_point(aes(model_2$fitted.values, model_2$residuals))