Loretta, who turns eighty this year, has just learned about blood pressure problems in the elderly and is interested in how her blood pressure compares to those of her peers. Specifically, she is interested in her systolic blood pressure, which can be problematic among the elderly. She has uncovered an article in a scientific journal that reports that the mean systolic blood pressure measurement for women over seventy-five is mmHg. Assume that the article reported correct information. Complete the following statements about the distribution of systolic blood pressure measurements for women over seventy-five.

(a) According to Chebyshev's theorem, at least ?56%75%84%89% of the measurements lie within 2 standard deviations of the mean, mmHg. (b) Suppose that the distribution is bell-shaped. If approximately 99.7% of the measurements lie between 114.0 mmHg and 148.2 mmHg, then the approximate value of the standard deviation for the distribution, according to the empirical rule, is .