Seniors at a local high school took both the AP Statistics exam and the AP Literature exam. On the Statistics test, the mean score was 2.4 with a standard deviation of 0.6. On the Literature test, the mean score was 2.65 with a standard deviation of 0.55. If you wanted to look at the combined scores (and assumed the tests were independent), what would their mean and standard deviation be?

these are the given answers:
A. 5.05, 0.66
B. 5.05, 1.15
C. 5.05, 1.07
D. 5.05, 0.82

Question

Seniors at a local high school took both the AP Statistics exam and the AP Literature exam. On the Statistics test, the mean score was 2.4 with a standard deviation of 0.6. On the Literature test, the mean score was 2.65 with a standard deviation of 0.55. If you wanted to look at the combined scores (and assumed the tests were independent), what would their mean and standard deviation be? 

these are the given answers: 
A.  5.05, 0.66 
B.  5.05, 1.15 
C.  5.05, 1.07 
D.  5.05, 0.82  <---
E.   5.05, 0.42

howard-wolowitz · Answer

am i right with D