how do I solve the following: 2. A set of data whose histogram is extremely skewed yields a mean and standard deviation of 70 and 12, respectively. What is the minimum proportion of observations that are between 46 and 94?
I have so far the mean is 70 and the stdev is 12. I know that I am suppose to use (1- 1 over k2(squared) 1/k2). I also know the answer is 75% just not sure how to get to 75%

Question

how do I solve the following: 2.	A set of data whose histogram is extremely skewed yields a mean and standard deviation of 70 and 12, respectively. What is the minimum proportion of observations that are between 46 and 94?
 I have so far the mean is 70 and the stdev is 12. I know that I am suppose to use (1- 1 over k2(squared) 1/k2). I also know the answer is 75% just not sure how to get to 75%