Final answer:
The arithmetic average return for Mary Ann's stock over the five years is 18.40 percent. The variance of the stock's returns over this period is 0.027850, and the standard deviation is 16.69 percent.
Step-by-step explanation:
To calculate the arithmetic average return on Mary Ann's stock over the past five years, we add up all of the annual returns and divide by the number of years. Hence, the calculation would be (46.00 + 28.00 + 31.00 - 33.00 + 20.00) / 5 = 92.00 / 5 = 18.40 percent.
To find the variance, we need to calculate the mean (which we found to be 18.40 percent), subtract each year's return from the mean, square the result, sum those squares, and divide by the number of observations minus one. Then, to find the standard deviation, we take the square root of the variance.
Calculations:
- Mean = 18.40%
- Variance = [((46.00 - 18.40)^2 + (28.00 - 18.40)^2 + (31.00 - 18.40)^2 + (-33.00 - 18.40)^2 + (20.00 - 18.40)^2) / (5 - 1)]
- Standard Deviation = sqrt(Variance)
Substituting the values and after calculation, we find:
- Variance = 0.027850
- Standard Deviation = 16.69%