Sec 1.3 - Density Curves and Normal Distributions
A histogram can be made by setting the height of the bars equal to the actual
count of a class or by setting it equal to the percent of that class with respect to the data
Using percents, if we set the width of the bars equal to one, then the total area of
the bars must be 1 (because the bars must add up to 100%).
a smooth approximation to a histogram
A density curve
is a curve that:
is always on or above the horizontal axis
has area exactly 1 underneath it
a smooth approximation to a histogram.
A density curve describes the overall pattern of a distribution.
The area under the curve between two values on the horizontal axis gives the
percent of the data that falls within that range of data.
The quartiles can be estimated using a density curve.
The median is the point at
which half the area under the curve lies to the right and half to the left.
the area to the left, and the third quartile has
of the area to the