This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Descriptive Statistics Measures of Central Tendency You should be able to . . . • Define the term measure of central tendency • Define and compute: – Mode – Median – Mean • Compare the measures of central tendency when distributions are skewed Measures of Central Tendency • Measures that describe where the center of a distribution of scores is located • Measures that represent the most typical or most representative scores in a distribution Three Measures of Central Tendency Mode Median Mean Mode • The most frequently occurring score in a frequency distribution • Simplest measure of central tendency Example: Friends Extro/ Introversion Extroverts Introverts # Friends Frequency # Friends Frequency 10 7 6 6 9 6 5 7 8 5 4 4 7 2 3 2 6 2 2 2 5 1 1 3 4 1 2 What are the modes? Extroverts Introverts # Friends Frequency # Friends Frequency 10 7 6 6 9 6 5 7 8 5 4 4 7 2 3 2 6 2 2 2 5 1 1 3 4 1 2 What are the modes? Extroverts Introverts # Friends Frequency # Friends Frequency 10 7 6 6 9 6 5 7 8 5 4 4 7 2 3 2 6 2 2 2 5 1 1 3 4 1 2 What are the modes? Extroverts Introverts # Friends Frequency # Friends Frequency 10 7 6 6 9 6 5 7 8 5 4 4 7 2 3 2 6 2 2 2 5 1 1 3 4 1 2 • Remember: The MODE is the class, NOT the frequency What is the mode? • There are two modes: 2 and 10 What is the mode? Median • The point in a frequency distribution that separates the top 50% of the scores from the bottom 50% • The score at the 50th percentile • Half of the scores lie above the median; half of the scores lie below the median Example: Odd number • Nine observations: 4 6 5 9 8 10 11 7 3 1. Order the observations 4 6 5 9 8 10 11 7 3 1. Order the observations 4 6 5 9 8 10 11 7 3 1. Order the observations 4 6 5 9 8 10 11 7 3 3 4 5 6 7 8 9 10 11 2. Find the middle position Middle position = (number of scores +1)/2 Middle position = (9+1)/2 = 5 3 4 5 6 7 8 9 10 11 2. Find the middle position Middle position = (number of scores +1)/2 Middle position = (9+1)/2 = 5 3 4 5 6 7 8 9 10 11 2. Find the middle position Middle position = (number of scores +1)/2 Middle position = (9+1)/2 = 5 3 4 5 6 7 8 9 10 11 2. Find the middle position2....
View
Full Document
 Fall '07
 Pfordesher
 Mean, middle position

Click to edit the document details