math
posted by devon on .
A fitness company surveyed the weights of its 90 costumers. Assume that the weights are normally distrubted with a mean of 162 lbs and a standard deviation of 3.5 lbs. If you select one of its costumers randomly, what is the probability that the costumer's weight is
a) more than 162 lbs?
b) more than 155 lbs?
c) less than 172.5 lbs?
d) between 158.5 lbs and 169 lbs?

Use
http://davidmlane.com/hyperstat/z_table.html
again.