Posted by Peter on .
Maria and Zoe are taking Biology 105 but are in different classes. Maria's class has an average of 78% with a standard deviation of 5% on the midterm, whereas Zoe's class has an average of 83% with a standard deviation of 12%. Assume that scores in both classes follow a normal distribution.
A. Convert Maria's midterm score of 84 to a standard z score.
which is correct?
a. 0.083
b. 0.5
c. 0.2
d. 1.2
e. 6
B Convert Zoe's midterm score of 89 to a standard z score.
a. 1.2
b. 0.5
c. 6
d. 0.917
e. 2.2
C. Who did better relative to her class?
a. Maria
b. Zoe
c. They performed the same.
d. Neither
e. Cannot determine

AP Stats 
Damon,
I will do the Maria part, then you do the rest
Mean = 78
score = 84
score above mean = 84  78 = 6
sigma = 5
6/5 = 1.2 standard deviations above mean