A new national survey found that Americans drink an average of 6 glasses of water daily, instead of the recommended 8. Assuming that the number of glasses of water is approximately normally distributed with a standard deviation of 1.7 glasses, what proportion of Americans drink more than the recommended amount?

Answer 1

Z = (score-mean)/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.