Unit 541/551

library(tidyverse)
library(janitor)
library(broom)

data541 <- read.csv("unit_541_practice_data.csv")
data541 %>% View()

groups <- data541 %>%
  group_by(group) %>%
  summarise_at(vars(happy),
               list(means = mean))

model <- data541 %>% lm(happy ~ group, .)

# create dummy variables
data541$group_dummy_1 <- ifelse(data541$group == "Group 1", 1, 0)
data541$group_dummy_2 <- ifelse(data541$group == "Group 2", 1, 0)
data541$group_dummy_3 <- ifelse(data541$group == "Group 3", 1, 0)

# create a linear model where 3 is the reference category
data541 %>% lm(happy ~ group_dummy_1 + group_dummy_2, .) %>% summary

# ANOVA
model %>%
  anova() %>%
  tidy()

summary(model)

# Unit 551
data551 <- read.csv("unit_551_practice_data.csv")
data551 %>% View()

# boxplot
data551 %>%
  ggplot(aes(x = method, y = bacteria)) +
  geom_boxplot()

# linear model
data551$method <- as.factor(data551$method)

model2 <- data551 %>%
  lm(bacteria ~ method, data = .)
summary(model2)

# ANOVA
model2 %>%
  anova() %>%
  tidy()