zoo::yearqtr

Seen most often in financial and business settings, the concept of 'quarters of a year' is important in time series analysis. The zoo package introduces the yearqtr class, which stores both the year and quarter components of a date.

In this exercise, you'll work with quarterly sales data, quarterly_data, and an index of dates of observations, date_index_quarter, with each observation occurring each quarter of the year (every three months).

The above datasets, as well as the ggplot2, zoo, and lubridate packages are available to you.

Create an index, index_yearqtr, by converting the date_index_quarter vector to the yearqtr class.
Create quarterly_sales, a zoo based on the data in quarterly_data and the index you created, index_yearqtr.
Add the x-axis label "Quarter", the y-axis label "Quarterly Sum ($100k)", and the title "Quarterly Sales Report".

Exercise

zoo::yearqtr

Instructions