A nationwide 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 nationalmeanscore for the writing section was50.2. Based on this information, complete the following statements about thedistributionof the scores on the writing section for the recent year.

(a) According to Chebyshev's theorem, at least?56%75%84%89%of the scores lie within 1.5standard deviationsof the mean,50.2. (b) Suppose that the distribution isbell-shaped. If approximately 68% of the scores lie between 40.3 and 60.1 , then the approximate value of the standard deviation for the distribution, according to the empirical rule, is ?.