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20. (L84) The chemistry test scores of 9 students were as follows: 100, 84, 91, 77, 69, 92, 93, 93, and 88. Use a TI-83 or TI-84 calculator to find the standard deviation of these chemistry test scores. The answer should be rounded to one decimal place. A. 5.4 B. 7.6 C. 8.9 D. 9.7 E. 11.3 21. (131) If m(x) - 2vx and m(n(x)) = 18vx3, find n(x). A. X3 B. 81x3 C. _ D. 9x3 E. 9x 22. (L77) In an arithmetic sequence, do = 42 and a21 = 117. What is a150? A. 564 B. 762 C. 848 D. 968 E. None of the above