Which of these statement accurately describes Chebychev's Inequality? For a data set, the proportion of values in the range “average ± z SDs” is

at least 1−1z2/
1
-
1
z
2

That the standard deviation is greater than the mean.

For a data set, the proportion of values in the range “average ± z SDs” is never more than 1−1z2/
1
-
1
z
2

That the mean is always greater than twice the median of a data set.