Weights of a certain model of fully loades gravel trucks follow a normal distrbution with mean = 6.4 tons and standard deviation = 0.3 ton. Waht is the probability that a fully loaded truck of this model is

a. less than 6 tons?
b. more that 7 tons?
c. between 6 and 7 tons?

1 answer

Z = (score-mean)/SD

a. Z = (6-6.4)/.3

Calcuate Z score and find its value in the table in the back of your stat text labeled something like "areas under normal distribution" to get the probability.

Use similar processes for b abd c.