A set of data is approximately normally distributed. In order from highest to lowest, list the range, the Interquartile Range (IQR), and the standard deviation.
A certain tree farm grew 4-, 5- and 6-foot trees. It grew 150 4-foot trees, 450 5-foot trees, and 400 6-foot trees. What was the average height of a tree that the farm grew? (Note: 1 foot = 12 inches.)