To determine the range of a data set, subtract the smallest number from the largest number.
From the given numbers of miles Ron biked:
- The smallest number is 28.
- The largest number is 49.
Calculating the range:
\[ \text{Range} = \text{Largest} - \text{Smallest} = 49 - 28 = 21 \]
Thus, the range of this data set is 21 miles.