Posted by Sue 620 on Thursday, June 13, 2013 at 7:58pm.
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, Friday, June 14, 2013 at 1:22pm
"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, Friday, June 14, 2013 at 2:01pm
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, Friday, June 14, 2013 at 2:05pm
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?
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