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15. Sample standard deviation is not a very useful dispersion measure because it is expressed in square units. 16. The Empirical Rule is based around three unique percentages: 63%, 96% and 99.7%. 17. Chebyshev's Theorem gives a very rough "at-least" percentage estimate. 18. A relative frequency distribution can be expressed as a percentage or a decimal. 19. Movies ranked by popularity are an example of the ratio level of measurement. 20. With the nominal level of measurement you can perform the mathematical operations of x and = but not + and - Problems: 1. There were only six students in Biology 220 class at Highline College Spring 2020. Their grades on Exam I were as follows: 92, 96, 61, 92, 79, and $4. Calculate the mean, the median (you must show the proper formulas for both calculations) and the mode. Is the mean value calculated here a statistic or a parameter? Explain 2. A sample study of registration records for a 400 level math class at UW Tacoma showed a mean age of 24 with a sample variance = 1.3. A few very young students skewed the mean in a negative direction. At least 90% of the class is between what two ages? (Solve using either Chebyshev or the Empirical Rule.)