2.3 Measures of Central Tendency

I. Mean, Median, and Mode

O Measure of Central Tendency: a value that represents a typical, or central, entry of a data setO Mean: sum of the entries

# of entries Population: Sample:

O Pg 60 TIY #1

O Median: the value that lies in the middle when the data is ordered

O Pg 61 TIY#2 & 3

O Mode: data entry that occurs with the most frequency (no mode, bimodal, multimodal)

O Pg 62 TIY #4 & 5

O Outlier: data entry far removed from the others

O If data has an outlier use the median not the mean as the best measure of central tendency

O Pg 63 TIY#6

II. Weighted Mean & the Mean of Grouped Data

O Weighted Mean: the mean of a data set whose entries have varying weights

w = weight of each entry x

Page 64 TIY #7

O Mean of a Frequency Distribution:

O Guidelines:1) Find the midpoint of each

class2) Find the sums of the

midpoints multiplied by the frequencies3) Find the sum of the

frequencies4) Divide #2 by #3.

Page 65 TIY #8

HomeworkO PAGES 68 – 73 O #16, 22, 30, 32, 40, 42, 44, 46