Final answer:
To find the annual effective yield of Joan's investment, you divide the end value of the investment ($1,621.40) by the start value ($1,420), raise this to the power of (1/number of years), and subtract 1. Doing this calculation shows Joan's investment had an annual effective yield of 14.18%.
Step-by-step explanation:
The annual effective yield of an investment is the percentage of interest that is earned on an investment over a year, taking into account the effects of compounding. To calculate the annual effective yield, we use the formula:
Annual Effective Yield = [(Ending Value / Beginning Value) ^ (1 / Number of Years)] - 1
In the student's case, Joan's investment at the start of the year was $1,420, and at the end of the year, her investment was worth $1,621.40.
To find the annual effective yield, we take the ending value and divide it by the beginning value:
(End Value / Start Value) = ($1,621.40 / $1,420)
This gives us a quotient of approximately 1.141831, which we can use in our formula for calculating the yield:
Annual Effective Yield = [1.141831^(1/1)] - 1
So, Annual Effective Yield = 1.141831 - 1 = 0.141831, or 14.18% when expressed as a percentage to two decimal places. Therefore, Joan's investment yielded an annual effective yield of 14.18%.