Anationwide test taken by high school sophomores and juniors has three sections, each scored on a scale of 20 to 80. in a recent year, the national mean score for the writing section was 51.2. based on this information, complete the folloiwng staements about the distribution of the scores on the writing section for the recent year.
1. according to chebyshev's theorem, at least % fo the scores lie within 2.5 standard deviations of the mean, 51.2.
2. suppose that the distribution is bell shaped. if approximately 99.7% of the scores lie between 23.6 and 78.8, then the approximate value of the standard deviation for the distribution, according to the empirical rule, is