mtcars.Rmd

---
title: "Uncertainty examples with mtcars"
output:
  github_document:
    toc: true
---



```{r setup}
library(tidyverse)
library(modelr)
library(brms)
library(tidybayes)
library(gganimate)
```


```{r}
mtcars %>%
  ggplot(aes(x = hp, y = mpg)) +
  geom_point()
```

```{r}
m_linear = brm(mpg ~ hp, data = mtcars)
```


```{r}
mtcars %>%
  data_grid(hp = seq_range(hp, n = 101)) %>%
  add_fitted_draws(m_linear, n = 100) %>%
  ggplot(aes(x = hp)) +
  geom_line(aes(y = .value, group = .draw), alpha = .2) +
  geom_point(aes(y = mpg), data = mtcars)
```


```{r}
mtcars %>%
  data_grid(hp = seq_range(hp, n = 101)) %>%
  add_fitted_draws(m_linear, n = 100) %>%
  ggplot(aes(x = hp, y = mpg)) +
  geom_line(aes(y = .value)) +
  geom_point(data = mtcars) +
  transition_manual(.draw)
```



```{r}
m_loglog = brm(mpg ~ hp, data = mtcars, family = lognormal)
```



```{r}
mtcars %>%
  data_grid(hp = seq_range(hp, n = 101)) %>%
  add_fitted_draws(m_loglog, n = 100) %>%
  ggplot(aes(x = hp, y = mpg)) +
  geom_line(aes(y = .value)) +
  geom_point(data = mtcars) +
  transition_manual(.draw)
```



```{r}
mtcars_clean = mtcars %>%
  mutate(transmission = factor(am, labels = c("automatic", "manual")))

m_loglog_trans = brm(mpg ~ hp * transmission, data = mtcars_clean, family = lognormal)
```

```{r}
mtcars_clean %>%
  data_grid(hp = seq_range(hp, n = 101), transmission) %>%
  add_fitted_draws(m_loglog_trans, n = 100) %>%
  ggplot(aes(x = hp, y = mpg, color = transmission)) +
  geom_line(aes(y = .value, group = paste(transmission, .draw)), alpha = .1) +
  geom_point(data = mtcars_clean)
```



```{r}
mtcars_clean %>%
  data_grid(hp = seq_range(hp, n = 101), transmission) %>%
  add_fitted_draws(m_loglog_trans, n = 100) %>%
  ggplot(aes(x = hp, y = mpg, color = transmission)) +
  geom_line(aes(y = .value)) +
  geom_point(data = mtcars_clean) +
  transition_manual(.draw)
```