1 / 15

Chapter 3 Measures of Central Tendency

Chapter 3 Measures of Central Tendency. I Mode A. Definition: the Score or Qualitative Category that Occurs With the Greatest Frequency 1. Mode ( Mo ) for the following data, number of required textbooks for Fred’s four classes, is 2. 2 1 2 3.

byron-pena
Download Presentation

Chapter 3 Measures of Central Tendency

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 3 Measures of Central Tendency I Mode A. Definition: the Score or Qualitative Category that Occurs With the Greatest Frequency 1. Mode (Mo) for the following data, number of required textbooks for Fred’s four classes, is 2. 2 1 2 3

  2. Table 1. Taylor Manifest Anxiety Scores • _______________________________ • (1) (2) f _______________________________ 74 1 73 1 72 0 71 2 70 7 Mo = 69 69 8 68 5 67 2 66 1 65 1 _______________________________ n = 28 _______________________________

  3. II Mean A. Definition: the Mean Is the Sum of Scores Divided by the Number of Scores B. Formula

  4. C. Summation Operator, (Greek capitol sigma) D. Mean Formula for a Frequency Distribution 1. k = number of class intervals

  5. Table 2. Taylor Manifest • Anxiety Scores • _________________ • (1) (2) (3) f _________________ 74 1 74 73 1 73 72 0 0 71 2 142 70 7 490 69 8 552 68 5 340 67 2 134 66 1 66 65 1 65 _________________ n = 28 1,936 _________________

  6. III Median (Mdn) • A. Definition: the Median Divides Data Into Two Groups Having Equal Frequency • 1. If n is odd and the scores are ordered, the median • is the (n + 1)/2th score from either end of the number line. • 2. If n is even, the median is the midway point • between the n/2th score and the n/2 + 1th • score from either end of the number line.

  7. B. Computational Examples 1. Determination of Mdn when n is odd 2. Determination of Mdn when n is even

  8. 3. Determination of Mdn when n is even (a) or odd (b), and the frequency of the middle score value is greater than 1

  9. 4. Determination of Mdn when n is even and the frequency of the middle score value is greater than 1

  10. C. Computation of Mdn for a Frequency Distribution 1. Formula when scores are cumulated from below Xll = real lower limit of the class interval containing the median i = class interval size n = number of scores fb = number of scores below Xll fi = number of scores in the class interval containing the median

  11. 2. Formula for the Mdn when scores are cumulated from above Xul = real upper limit of class interval containing the median fa = number of scores above Xul

  12. Table 3. Taylor Manifest Anxiety Scores _____________________________ __________________________ 74 1 1 73 1 2 72 0 2 71 2 4 70 7 11 69 8 17 19 68 5 9 67 2 4 66 1 2 65 1 1 __________________________ n = 28 __________________________

  13. IV Relative Merits of the Mean, Median, and Mode V Location of the Mean, Median, and Mode in a Distribution

  14. VI Mean of Two or More Means A. Weighted Mean VII Summation Rules A. Sum of a Constant (c) n terms

  15. B. Sum of a Variable (Vi) C. Sum of the Product of a Constant and a Variable D. Distribution of Summation

More Related