SOLUTION: The mean weight of 200 students is 140 pounds,and the standard deviation is 10 pounds.If we assume that the weights are normally distributed,evaluate thefollowing: (i)The expected

Question 1019416: The mean weight of 200 students is 140 pounds,and the standard deviation is 10 pounds.If we assume that the weights are normally distributed,evaluate thefollowing:
(i)The expected number of students that weigh between 110and145 pounds
(ii)The expected number of students that weigh lessthan 120pounds.
(iii)The expected number of students that weigh more than 170pounds
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
z=(x-mean)/sd
between 110 and 145 is a z between -30/10 (-3) and a z of (5/10) or 1/2
That probability is 0.6901. and that is 138 students.
--------------------------
Fewer than 120 pounds is fewer than -2 sd. The probability is 0.02275, and that is 5 students, rounded.
=========================
more than 170 pounds is more than +3 sd. The probability is 0.00134, and that would be 0 students, rounded (Expected value is 0.27)
RELATED QUESTIONS
10. The mean weight of 500 male students at a certain college is 151 pounds (lb), and the (answered by Fombitz)

In the United States, the National Health Survey has determined that women�s weights are... (answered by stanbon)

Newborn elephant calves usually weigh between 200 and 250 pounds. Until October 2006,... (answered by Boreal)

Airlines have to estimate the weights of passengers. Assume that men have weights that... (answered by stanbon)

The capacity of a lift is 15 people or 2385 pounds. The capacity will be exceeded if 15... (answered by stanbon)

The capacity of a lift is 12 people or 2028 pounds. The capacity will be exceeded if 12... (answered by stanbon)

Weights of the Pacific yellowfin tuna follow a normal distribution with mean 68 pounds... (answered by ewatrrr)

The weights (in kg) of the students in a school is normally distributed with standard... (answered by VFBundy)

Assume that the weight of all employees who work on the forty-first floor of a city... (answered by stanbon)