These two plots show the same general trend of increasing calls overall throughout the years, but do deviate from each other in terms of the types of noise complaints coming in. This is worth investigating further. 

Testing for Stationarity: Unit Root Tests

In order to understand if the trends are stationary or if they change over time, I worked with time series data to identify unit roots. 

Using rolling means to visually assess stationarity

First, I created a timeseries column "ts" which extracted the month and year for calls. Grouping by this new metric, I was able to create a count of noise complaint call per month since 2010. Because there are relatively few months worth of data (fewer than 100), it may be possible to view these trends visually. The following plots show the data over time, with a rolling mean window of 10.