A Data Set Has a Mean of 50 and a Standard

Multiple Choice

A data set has a mean of 50 and a standard deviation of 10. Which of the following might possibly be true?

A) More than 90% of the data values are between 20 and 80.
B) No more than 50% of the data values are between 30 and 70.
C) No less than 30% of the data values are less than 30 or greater than 70.
D) At least 15% of the data values are less than 20 or greater than 80.