What percentage (%) of iPods . . .

a. has a likelihood of failure greater than 25%?

b. has a likelihood of failure greater than 10%?

c. has a likelihood of failure less than 20%?

d. has a likelihood of failure less than 5%?

e. has a likelihood of failure between 15% and 30%?

f. has a likelihood of failure between 11% and 18%?

A survey conducted in 2005 (www.macintouch.com) asked a large number of iPod owners whether their iPod had ever failed (completely stopped working). Based on their results, it was estimated that the likelihood of experiencing a failure was normally distributed, with an average likelihood of failure (μ) of 13.70%, with a standard deviation (σ) of 7.54%.