A variable has the density curve whose equation is y = 1 for 0 < x < 1, and y = 0 otherwise.

a. Graph the density curve of this variable.

b. Show that the area under this density curve to the left of any number x between 0 and 1 equals x.

What percentage of all possible observations of the variable

c. lie between 1/4 and 3/4?

d. exceed 7/8?

Applying the Concepts and Skills