1. FREQUENCY DISTRIBUTIONS What is a Frequency Distribution? What is a Frequency Distribution? What is a Frequency Distribution? What is a Frequency Distribution? What are Frequency Distributions Used For? What are Frequency Distributions Used For? What are Frequency Distributions Used For? What are Frequency Distributions Used For? Ways of Displaying Frequency Distributions Ways of Displaying Frequency Distributions Ways of Displaying Frequency Distributions Ways of Displaying Frequency Distributions Describing Frequency Distributions Describing Frequency Distributions Describing Frequency Distributions Describing Frequency Distributions Frequency Distribution Statistics Frequency Distribution Statistics Frequency Distribution Statistics Frequency Distribution Statistics

2. What is a Frequency Distribution? raw score distribution: list of each individual’s score raw score distribution: list of each individual’s score frequency distribution: list of each score that appears and how many times each score occurs frequency distribution: list of each score that appears and how many times each score occurs

3. What are Frequency Distributions Used For? Summarize a large set of data. Summarize a large set of data. Describe the shape of a distribution. Describe the shape of a distribution. Needed for inferential statistics. Needed for inferential statistics.

4. Ways of Displaying Frequency Distributions Table Table Frequency Polygon Frequency Polygon Histogram Histogram Bar Graph Bar Graph

5. Frequency Distribution Table xf 75 63 58 48 39 210 17

6. Frequency Polygon Best for quantitative/continuous data. Best for quantitative/continuous data. Study Time in Hours f 0123401234 5 10 15

7. Histogram Best for quantitative/continuous data. Best for quantitative/continuous data. Study Time in Hours f 0 1 2 3 4 5 10 15

8. Bar Graph Best for qualitative/discrete variables. Best for qualitative/discrete variables. f Bus Psy Bio Art 5 10 15 Major

9. Guidelines for Graphs Label units. Label units. Make axes proportional (y axis should be 2/3 to 3/4 length of x axis). Make axes proportional (y axis should be 2/3 to 3/4 length of x axis). Make bars equal width. Make bars equal width. Keep it simple. Keep it simple.

10. Describing Frequency Distributions symmetrical: same on both sides symmetrical: same on both sides

11. skewed: scores piled on one side skewed: scores piled on one side positive skew negative skew body tail

12. kurtosis: steepness kurtosis: steepness leptokurtic platykurtic mesokurtic

13. Frequency Distribution Statistics relative frequency: proportion of scores that are x relative frequency: proportion of scores that are x cumulative frequency: number of scores up to and including x cumulative frequency: number of scores up to and including x percentile rank: percentage of scores up to and including x percentile rank: percentage of scores up to and including x percentile: x score at a percentile rank percentile: x score at a percentile rank