Lesson 7

Mean or Median

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
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TIMS Challenge

This problem can serve as a Problem of the Week.

She needs to get 18 or more words correct. Students can solve this problem using connecting cubes or trial and error. Calculators should also be made available. Students can multiply 17 by 6 to get the total number of points Felicia needs for an average of 17 points per test. 17 × 6 = 102. Then they can subtract her total for the first five tests to see what she needs on the sixth test. Some students may justify a score as low as 15. A score of 15 will give an average of 16.5. If rounding is allowed, this could be rounded to 17. For the mean to equal exactly 17, Felicia must spell 18 words correctly on the sixth test.

V. Averaging Scores

Every week Felicia takes a spelling test on 20 spelling words. Mr. Moreno uses the mean to average test scores. Felicia wants her average number of correct words to be 17 or greater. She spelled the following number of words correctly on the first 5 tests: 15, 18, 15, 16, and 20. What must she score on her sixth test so that her average on all six will be at least 17? Explain your thinking.