Examples: Suppose $500,000 is invested in stock of xyz company. The standard deviation the over trading year is 7%. Hint, following the normal distribution, the one-sided 95% confidence level has az- score of 1.645. Examples: Suppose $500,000 is invested in stock of xyz company. The standard deviation the over trading year is 7%. Hint, following the normal distribution, the one-sided 95% confidence level has az- score of 1.645