Section 2.4 notes continued Statistics Section 2.4 notes continued

Finding the mean from a frequency table – Because the actual data is lost in a freq table, the best we can do is to estimate the mean. For each class, find the class midpoint and multiply that number by the corresponding frequency. Add those products together and then divide by the total frequency.

Skewness Figure 2-13 (b) Mode = Mean = Median SYMMETRIC

Skewness SYMMETRIC SKEWED LEFT (negatively) Figure 2-13 (b) Figure Mode = Mean = Median SYMMETRIC Mean Mode Median Figure 2-13 (a) SKEWED LEFT (negatively)

Skewness SYMMETRIC SKEWED LEFT SKEWED RIGHT (negatively) (positively) Figure 2-13 (b) Mode = Mean = Median SYMMETRIC Mean Mode Mode Mean Median Median Figure 2-13 (a) SKEWED LEFT (negatively) SKEWED RIGHT (positively) Figure 2-13 (c)