calculating upper and lower quartiles The number of goals scored by a football team during a months worth of matches is recorderd. They scored $0$ goals $4$ times, $1$ goal $6$ six times and $2$ goals $3$ times. Calculate the lower and upper quartiles. Would it simply be this?: lower quartile is the $3.5$th value which is zero, and upper quartile is the $10.5$th value which is $2$?

We have data on 4 + 6 + 3 = 13 games. $13 \cdot 0.25 = 3.25$, and $13 \cdot 0.75 = 9.75$. We round these to $3$ and $10$, respectively. We line up all our values in order: $$ 0\; 0\; 0\; 0\; 1\; 1\; 1\; 1\; 1\; 1\; 2\; 2\; 2 $$

The third value is $0$. the 10th value is $1$.