1. A stock has experienced the following returns over the past 4 years: 15%, 12%, 9%, 18%. The standard deviation of these returns is 3.87%. Given this, at a 95% confidence level, which of the following returns would be considered abnormally high?
   1. 18%
   2. 20%
   3. 22%
   4. 24%

1. IV only
2. III and IV only
3. II, III, and IV only
4. I, II, III, and IV