The lifetimes of a particular brand of DVD player are normally distributed with a mean of eight

Question:

The lifetimes of a particular brand of DVD player are normally distributed with a mean of eight years and a standard deviation of six months. Find each of the following probabilities where x denotes the lifetime in years. In each case, sketch the probability.

a. P(7 ≤ x ≤ 9)

b. P(8.5 ≤ x ≤ 9.5)

c. P(6.5 ≤ x ≤ 7.5)

d. P(x ≥ 8)

e. P(x ≤ 7)

f. P(x ≥ 7)

g. P(x ≤ 10)

h. P(x > 10)