1. 2.3 Measures of Central Tendency measure of central tendency - mean - population mean:sample mean: median - mode -

2. Ex: Find the mean median and mode of the sample ages of a calculus class at UGA. Which measure of central tendency best describes a typical entry? 18, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21, 21, 22, 22, 23, 23, 23, 23, 24, 24, 65

3. *In the case where some data entries have a greater impact on the mean than other entries, we find the weighted mean. weighted mean -,where w is the weight of each entry x. Ex: Find the weighted mean.

4. The mean of a frequency distribution for a sample is,where x and f are the midpoints of the frequencies of a class * Let's use our height data to find the mean of the frequency distribution.

5. The shape of distributions is revealed by graphing frequency distributions. The shape can be: (p. 61) 1. symmetric - 2. uniform - 3. skewed left - 4. skewed right - * the mean will always fall where the distribution is skewed!