Final answer:
About 50% of Brad's fantasy football leagues have fewer than 10 teams, as the median value provided in the five-number summary is 10.
Step-by-step explanation:
The five-number summary for the number of teams in each of Brad's fantasy football leagues includes the minimum (Min), first quartile (Q1), median, third quartile (Q3), and maximum (Max) values.
The median in this summary represents the point below which 50% of the data falls. In Brad's leagues, the median is 10, meaning that 50% of the leagues have fewer than 10 teams.
It is important to remember that the median splits the dataset into two halves, with one half having values below the median and the other half having values above it.