At King Kong High School, the average weight of senior boys is 168 lbs. with a standard deviation of 7 lbs. The average weight for senior girls is 117 libs. with a standard deviation of 5 lbs. Suppose a new distribution is created by adding the boys' weights and the girls' weights together. Assuming that the weights for boys and girls are independent, which of the following is true?

I. The mean of this new distribution is 168+117.
II. The standard deviation of this new distribution is 5+7.
III. The variance of this new distribution is 5^2+7^2

Question

At King Kong High School, the average weight of senior boys is 168 lbs. with a standard deviation of 7 lbs. The average weight for senior girls is 117 libs. with a standard deviation of 5 lbs. Suppose a new distribution is created by adding the boys' weights and the girls' weights together. Assuming that the weights for boys and girls are independent, which of the following is true? 

I. The mean of this new distribution is 168+117. 
II. The standard deviation of this new distribution is 5+7. 
III. The variance of this new distribution is 5^2+7^2

hockeychick23 · Answer

A. I and III only
B. II only
C. I and II only
D. I, II, and III
E. I only

dan815 · Answer

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