Chapter 3 Problems

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2. No single method always produces a good, representative value. 
   Therefore, there are three methods for measuring central 
   tendency, each with advantages and disadvantages.
4. The median is used instead of the mean when there is a skewed 
   distribution (few extreme scores), an open-ended distribution, 
   undetermined scores, or an ordinal scale.
6. The mode is preferred when the scores are measured on a 
   nominal scale.
8. a. Graphic of bar graph with Mean = 7.8, Median = 8.5, and 
      Mode = 9.0
   b. Mean = 78/10 = 7.8; Median = 8.5; and Mode = 9
10. a. Graphic of a bar graph. Unable to duplicate here.
    b. Mean = 30/10 = 3
    c. The median is still X = 3 (unchanged). The new mean is 
       70/10 = 7
12. Sum of X = 1300
14. a. Mean = 120 (the old mean is multiplied by 6)
    b. Mean = 25 (the old mean is increased by 5)
16. a. The mean will increase because the new score is greater 
       than the average for the original sample.
    b. The mean will decrease because the new score is lower than 
       the average for the original sample.
    c. The mean will stay the same, because the new score is 
       exactly equal to the average for the original sample.
18. For the original sample, sum of X = 5(21) = 105. When the 
    new score is added, Sum of X = 6(25) = 225. The score that 
    was removed is X = 5.
20. The original samples have sum of X = 12 and sum of X = 70. 
    The combined sample has sum of X = 82 and n = 10. The mean 
    for the combined sample is 82/10 = 8.2.
22. It is impossible for 60% of the scores to be greater than 
    the median (answer b).
24. a. mode = 2
    b. median = 2.5
    c. You cannot find the total number of absences (sum of X) 
       for this class.
26. a. Independent variable is the brand of coffee. Dependent 
       variable is the flavor rating.
    b. nominal
    c. bar graph (coffee brand is a nominal scale)
    d. Graphic of bar graph. Unable to duplicate here.
28. Graphic of a bar graph. Unable to duplicate here.