Answer:
The correct option is b.
Step-by-step explanation:
The formula for standard deviation is
where, 
is mean of the data and n is number of observation.
The variance of a stock's returns can be calculated by the above formula.
Variance of stock's returns is the average value of squared deviations from the mean.
Therefore the correct option is b.
Answer:
a i think
Step-by-step explanation:
The worth of Sarah's investment when she is 68 is $14,728.51.
<h3>What is the worth of the investment?</h3>
The formula that can be used to determine the worth of the investment is:
FV = P (1 + r)^n
FV = Future value
P = Present value
R = interest rate
N = number of years = 68 - 18 = 50
$500 x (1.07)^50 = $14,728.51
To learn more about future value, please check: brainly.com/question/18760477
