Please show work, thank you in advance.

If the distribution of possible future sales values is normal, then the probability that actual sales will be the expected value plus or minus one standard deviation is approximately?

1. 50%
2. 95%
3. 68% (correct)
4. 30%

Assuming a normal distribution, if the average return on an investment is 15%, which of the following standard deviations represents the highest risk?

1. 5%
2. 11%
3. 0%
4. 15% (correct)