A particular internet stock had an analysis of returns run over the last 10 years. Results indicated a NORMAL distribution curve and the standard deviation was calculated to be 7.5%, with a MEAN of 10.5%. Which of the following statements is true?

68% of the expected returns would be negative.

all of the above

68% of the expected returns would fall between -18.0% and 18.0%

95% of the expected returns would fall between -15.0% and 15.0%