Posted by Harley on .
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?

statistics 
PsyDAG,
Z = (scoremean)/SD
a. Z = (66.4)/.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.