Which of the Following Statements About Probability of Occurrence Is

Multiple Choice

Which of the following statements about probability of occurrence is correct?

A) The range of values found by adding and subtracting one standard deviation to the mean of the random variable accounts for 68.26 percent of the area under the curve.
B) The range of values found by adding and subtracting two standard deviations to the mean of the random variable accounts for 68.26 percent of the area under the curve.
C) The range of values found by adding and subtracting two standard deviations to the mean of the random variable accounts for 99.74 percent of the area under the curve.
D) All of the above are incorrect.