Applet Exercise demonstrates that probability is equal to area under a curve. Given that college students sleep

Question:

Applet Exercise demonstrates that probability is equal to area under a curve.
Given that college students sleep an average of 7 hours per night, with a standard deviation equal to 1.7 hours, use the scroll bar in the applet to find:
a. P(a student sleeps between 5 and 9 hours)
b. P(a student sleeps between 2 and 4 hours)
c. P(a student sleeps between 8 and 11 hours)