Suppose that a histogram of a data set is approximately symmetric and bell shaped. Approximately what percent of the observations are within two standard deviations of the mean? 50%

68%

95%

99.7%

Suppose that a histogram of a data set is approximately symmetric and "bell shaped". Approximately, what percent of the observations are within three ...

Three-sigma rule The three-sigma rule is also known as the 68-95-99.7 rule. According to the three-sigma rule, in a normal distribution most...

a is the correct

answer: x=60