15 A random sample of ten \(\mathrm { CO } _ { 2 }\) emissions was selected from the Large Data Set.
The emissions in grams per kilogram were:
$$\begin{array} { l l l l l l l l l l }
13 & 45 & 45 & 0 & 49 & 77 & 49 & 49 & 49 & 78
\end{array}$$
15
- Find the standard deviation of the sample.
15
- An environmentalist calculated the average \(\mathrm { CO } _ { 2 }\) emissions for cars in the Large Data Set registered in 2002 and in 2016.
The averages are listed below.
| Year of registration | 2002 | 2016 |
| Average \(\mathbf { C O } _ { \mathbf { 2 } }\) emission | 171.2 | 120.4 |
Fully justify your answer.
\begin{center}
\begin{tabular}{|l|l|}
\hline
& \begin{tabular}{l}