• Density curves are always on or above the horizontal axis.
• The area under the curve and above any range of values is the proportion of all observations that fall in that range. (the relative frequency, I.e.)
• The area below the curve is EXACTLY 1 (because the relative frequencies sum to 1).
• The pth percentile on a density curve is the point where p percent of the area lies to the left of that point and the remaining (100-p) percent lies to the right of that point