The shape is a normal (or bell) shaped distribution. If many of the participants had stated that they owned 70 to 90 compact disks and very few reported owning in the 0 to 20 range, then the distribution would have been negatively skewed. If many had reported owning between 0 and 20 compact disks and only a few reported owning between 70 and 90 compact discs, then the distribution would have had a positive skew. To get a rectangular distribution, there would have to be a roughly equal number of compact disks reported for each interval.