```
ggplot(cereal, aes(x = rating)) +
geom_density()
```

Alternatively, you can put the `aes(x = rating)`

within
the `geom_density()`

call.

```
ggplot(cereal) +
geom_density(aes(x = rating))
```

```
ggplot(cereal, aes(x = rating)) +
geom_histogram()
```

`## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.`

```
ggplot(cereal, aes(x = rating)) +
geom_histogram(fill = 'skyblue') +
scale_y_continuous(expand = expansion(add = c(0, 1)))
```

`## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.`

Note that `fill = '...'`

is not inside `aes()`

because it does not map back to a variable in the data. It is just a
stylistic choice. You may also choose other expansion parameters. I
chose `add = c(0, 1)`

to add 0 units of padding at the lower
end and 1 unit of padding at the upper end. Unfortunately this causes
non-integer breaks to appear in the y-axis by default but this could be
fixed by adding, for example `breaks = c(0, 4, 8)`

to the
call to `scale_y_continuous()`

.

```
ggplot(cereal, aes(x = manufacturer, y = rating)) +
geom_boxplot()
```

```
ggplot(cereal, aes(x = manufacturer, y = rating)) +
geom_boxplot(fill = 'oldlace', outlier.shape = 1)
```

*Bonus content*: You mightâ€™ve noticed that the names of the
manufacturers are long and overlap one another. This can be fixed by
customizing the x-axis labels so that the labels wrap onto multiple
lines of text as follows. I used `width = 15`

to split lines
every 15 characters, but other numbers could be used.

```
ggplot(cereal, aes(x = manufacturer, y = rating)) +
geom_boxplot(fill = 'oldlace', outlier.shape = 1) +
scale_x_discrete(labels = function(x) stringr::str_wrap(x, width = 15))
```

```
ggplot(cereal, aes(x = sugars, y = rating)) +
geom_point()
```

```
ggplot(cereal, aes(x = sugars, y = rating)) +
geom_point() +
geom_smooth(method = lm)
```

`## `geom_smooth()` using formula = 'y ~ x'`

The default for `geom_smooth()`

is `se = TRUE`

.
The standard error around the trend is shown as a shaded region.

```
ggplot(cereal, aes(x = sugars, y = rating)) +
geom_point() +
geom_smooth(method = lm) +
facet_wrap( ~ type)
```

`## `geom_smooth()` using formula = 'y ~ x'`

*Bonus content*: As there are only a handful of hot
cereals,all with very low sugar content and moderate to high health
rating, we have a lopsided looking plot. Also, the standard errors of
rating extend beyond the 0-100 range. We would have to use a special
model to fix that problem if we were really doing a formal analysis
here. I will fix it for plotting purposes by allowing the x-axes to vary
by facet (`scales = 'free_x'`

) and using
`coord_cartesian()`

to truncate the y-axis so that the
standard error envelope outside of 0-100 isnâ€™t shown.

```
ggplot(cereal, aes(x = sugars, y = rating)) +
geom_point() +
geom_smooth(method = lm) +
facet_wrap(~ type, scales = 'free_x') +
coord_cartesian(ylim = c(0, 100))
```

`## `geom_smooth()` using formula = 'y ~ x'`