Answer
$Q_1=36.85~miles~per~gallon$
$Q_2=38.35~miles~per~gallon$
$Q_3=41.0~miles~per~gallon$
Work Step by Step
The values in ascending order: 31.5, 34.3, 34.5, 35.5, 36.0, 36.3, 37.4, 37.5, 37.8, 37.9, 38.0, 38.3, 38.4, 38.8, 39.3, 39.5, 40.1, 40.6, 41.4, 41.5, 42.3, 42.7, 43.5, 47.5
There are 24 observations. The second quartile (median) is the mean between the 12th and the 13th observations
$Q_2=median=\frac{38.3+38.4}{2}=38.35$
The bottom half of the data: 31.5, 34.3, 34.5, 35.5, 36.0, 36.3, 37.4, 37.5, 37.8, 37.9, 38.0, 38.3. $Q_1$ is the median of these values.
$Q_1=\frac{36.3+37.4}{2}=36.85$
The top half of the data: 38.4, 38.8, 39.3, 39.5, 40.1, 40.6, 41.4, 41.5, 42.3, 42.7, 43.5, 47.5. $Q_3$ is the median of these values.
$Q_3=\frac{40.6+41.4}{2}=41.0$
