Write a function to compute the mean and standard deviation of a time series, and apply it to the
PBSdata. Plot the series with the highest mean, and the series with the lowest standard deviation.
GGally::ggpairs()to look at the relationships between the STL-based features for the holiday series in the
seasonal_trough_yearto factors, as shown in Figure 4.3. Which is the peak quarter for holidays in each state?
Use a feature-based approach to look for outlying series in the
PBSdata. What is unusual about the series you identify as “outliers.”