Try this solution (see the attachment); it consists of 5 basic steps.
The answers are marked with red and green colour.
Answer:
The answer is nine-halves, the last option.
B
Step-by-step explanation:
Standard deviation is the average distance away from the mean, thus B is correct
x=2.7 x 10*-3
-815x=2.24
x=-2.24/815
