Posted by Sue 620 on .
The International Bottled Water Association says that Americans on the average drink 4.6 (8oz.) servings of water a day. Assume that the number of 8oz. servings of water is approximately normally distributed with a standard deviation of 1.4 servings. (Give your answers correct to four decimal places.)
(b) What proportion of Americans drink less than half the recommended 8 servings?

Math help 
PsyDAG,
"less than half" = less than 2.3
Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score. 
Math check 
Tom7,
z=(82.3)/1.4=4.07 graph 0.99998
is this the right way and how do you change the graph numbers since they are all 9's that would need to be rounding? 
Math help 
Sue 620,
I worked it and got a different answer for the graph number 0.9893 and tom worked and got something totally different, what are we doing wrong, trying to work together on some of these?