The range is from 3 to 6, and the smallest fraction is 1/2, so the line is 3 units long divided into 6 parts, and 3 and 6 are points 0 and 6.
The end points 3 (left) and 6 (right) are part of the data, so mark and label them. 3 1/2 is 1 unit from the left so mark and label it; 4 1/2 is the next at 3 units; 5 at 4 units; 5 1/2 at 5 units. Place crosses above the marks, one cross for each mark except at 5 1/2 when 2 crosses are stacked. The most miles walked is 6 and the least 3. There are 7 crosses, so the data may be showing the number of miles walked each day in a week.