We will dive into the analysis stage with the following steps:
- Let's start by looking at whether there is an overall trend of how mpg changes over time on average. We first want to group the data by year:
In : grouped = vehicles.groupby("year")
- Next, we want to compute the mean of three separate columns by the previous grouping:
In : averaged = grouped['comb08', 'highway08','city08'].agg([np.mean])
This produces a new data frame with three columns containing the mean of comb08, highway08, and city08 variables, respectively. Notice that we are using the mean function supplied by NumPy (np).
- To make life easier, we will rename the columns and then create a new column named year, which contains the data frame's ...