Exercise 2.1

library(fpp2)
library(ggplot2)

Using the help function to explore what the series `gold`, `woolyrnq` and `gas` represent.

gold - Daily morning gold prices in US dollars. 1 January 1985 – 31 March 1989.
woolyrnq - Quarterly production of woollen yarn in Australia: tonnes. Mar 1965 – Sep 1994.

gas - Australian monthly gas production: 1956–1995.

help("gold")
ggtsdisplay("gold")

help("woolyrnq")
ggtsdisplay("woolyrnq")

help("gas")
ggtsdisplay("gas")

Using autoplot() to plot each of these in separate plots.
```
autoplot(gold)
```
```
autoplot(woolyrnq)
```
```
autoplot(gas)
```

Finding the frequency of each series by applying the frequency() function.

frequency(gold)

## [1] 1

frequency(woolyrnq)

## [1] 4

frequency(gas)

## [1] 12

Using which.max() to spot the outlier in the gold series and showing which observation it was.
```
which.max(gold)
```
```
## [1] 770
```
```
gold[which.max(gold)]
```
```
## [1] 593.7
```