The Empirical Rule states that: A) for a bell shaped frequency distribution, approximately 75% of the observations are in the range of plus or minus one standard deviation. B) for a positively skewed frequency distribution, approximately 75% of the observations are in the range of plus or minus one standard deviation. C) for a bell shaped frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation. D) for a positively skewed frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation.