6. Correct. The answer is true

(a) Weights recorded as being between 120 and 155 lb can actually have any value from 119.5 to 155.5, assuming they are recorded to the nearest pound. First, you should standardize the random variable in the following way:

119.5 lb in standard units = (119.5-151)/15 = -2.10

155.5 lb in standard units = (155.5-151)/15 = 0.30

P(-2.10 ≤ X≤ 0.30)=

Using the standard normal distribution table, we have that:

P(-2.10 ≤ X≤ 0.30) = 0.4821 + 0.1179

P(-2.10 ≤ X≤ 0.30) = 0.60

Then the number of employees weighing between 120 and 155 lb is 600*(0.60) = 360.

(b) Employees weighing more than 185 lb must weigh at least 185.5 lb. First, you should standardize the random variable in the following way

185.5 lb in standard units = (185.5-151)/15 = 2.30

P(X > 2.30) =

Using the standard normal distribution table, we have that:

P(X > 2.30) = 0.50 - 0.4893

P(X > 2.30) = 0.0107

Then, the number of employees weighing more than 185 lb is 600(0.0107) = 6. The above results may be summarized as follows:

P(119.4 ≤ W ≤ 155.5) = 0.600

P(W ≥ 185.5) = 0.0107