Boxes of floor tiles are to be offered for sale at a special price of $75. The boxes claim to contain at least 100 tiles each.

a. Why would it be preferable to use a stem-and-leaf diagram rather than a bar chart to represent the numbers of tiles, which are 112, 116, 107, 108, 121, 104, 111, 106, 105 and 110?

b. How may the seller benefit if the numbers 12, 16, 7, 8, 21, 4, 11, 6, 5 and 10 are used to draw the stem-and leaf diagram instead of the actual numbers of tiles?