In: Finance
Over the past five years, a stock produced returns of 14%, 22%, -16%, 4%, and 11%. If the returns are normally distributed, what is the probability that an investor in this stock will NOT lose more than 7.4% nor earn more than 21.4% in any one given year? (Hint: Find average return and standard deviation first.)
Year | Return (%) |
1 | 14 |
2 | 22 |
3 | -16 |
4 | 4 |
5 | 11 |
Description | Value | Comments |
Average | 7 | Sum of returns (35) / no. of returns (5) |
Standard Deviation | 12.86856635 | stdev.p formula for returns in excel |
In order to calculate probability of specific returns, we will determine the Z score using the below formula and then reference the Z score in the Z table to find the corresponding P value.
Z Score = (X-Mean) / Standard Deviation; where X is the random value
X < or = -7.4 | |
Z score (using above formula) | -1.12 |
Referencing in z score table we have P value of 0.1314 or 13.14% |
Probability of return less than -7.4% = 13.14%
X > or = 21.4 | |
Z score (using above formula) | 1.12 |
Referencing in z score table we have P value of 0.1314 or 13.14% |
Probability of return greater than 21.4% = 13.14%
Probability of return not less than -7.4% nor greater than 21.4% = Total probability - Probability of return less than -7.4% - Probability of return greater than 21.4% = [1 - 0.134 - 0.134)] = 0.732 or 73.2%