134. The article “Characterization of Room Temperature Damping in Aluminum-Indium Alloys” (Metallurgical Trans., 1993: 1611–1619) suggests that Al matrix grain size (mm) for an alloy consisting of 2% indium could be modeled with a normal distribution with a mean value 96 and standard deviation 14.

a. What is the probability that grain size exceeds 100?

b. What is the probability that grain size is between 50 and 80?

c. What interval

(a,

b) includes the central 90% of all grain sizes (so that 5% are below a and 5%

are above b)?