29. Trimmed Mean Because the mean is very sensitive to extreme values, we say that it is not a resistant measure of center. The trimmed mean is more resistant. To find the 10% trimmed mean for a data set, first arrange the data in order, then delete the bottom 10% of the values and the top 10% of the values, then calculate the mean of the remaining values. For the weights of the bears in Data Set 6 from Appendix B, find

(a) the mean;

(b) the 10% trimmed mean;

(c) the 20% trimmed mean. How do the results compare?

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Daily Low Temperature

(°F) Frequency 35–39 1 40–44 3 45–49 5 50–54 11 55–59 7 60–64 7 65–69 1 Daily Precipitation

(inches) Frequency 0.00–0.49 31 0.50–0.99 1 1.00–1.49 0 1.50–1.99 2 2.00–2.49 0 2.50–2.99 1 Table for Exercise 27 Speed Frequency 42–45 25 46–49 14 50–53 7 54–57 3 58–61 1 Table for Exercise 28 Temperature Frequency 96.5–96.8 1 96.9–97.2 8 97.3–97.6 14 97.7–98.0 22 98.1–98.4 19 98.5–98.8 32 98.9–99.2 6 99.3–99.6 4