SOLUTION: The average American man consumes 9.5 grams of sodium each day. Suppose that the sodium consumption of American men is normally distributed with a standard deviation of 0.9 grams.

Click here to see ALL problems on Probability-and-statistics

Question 1188012: The average American man consumes 9.5 grams of sodium each day. Suppose that the sodium consumption of American men is normally distributed with a standard deviation of 0.9 grams. Suppose an American man is randomly chosen. Let X = the amount of sodium consumed. Round all numeric answers to 4 decimal places where possible.
a. What is the distribution of X? X ~ N(
9.5
Correct,
.9
Correct)
b. Find the probability that this American man consumes between 9.2 and 10.9 grams of sodium per day.
.5707
Correct
c. The middle 20% of American men consume between what two weights of sodium?
Low:
High:

Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website!
the middle 20% is between the 40th and 60th percentiles or z=-0.253 to z=+0.253
0.253=(x-mean)/sd for upper limit
0.253=(x-9.5)/0.9
0.2280=x-9.5
x=9.7280 gms upper limit. Symmetrical here so lower limit is 9.2720 gms.
(9.2720, 9.7280) gms