This learning activity consists of a variety of problems from Chapters 13-15. Include a title page with your assignment in current APA format. Spaces for answers are provided. Submit your assignment as a Word document.
1. Calculate the mean, median, mode, standard deviation, and range for the following sets of measurements (fill out the table):
a. 9, 7, 6, 6, 2
b. 12, 10, 9, 8, 6
c. 82, 82, 82, 82, 82
d. 12, 10, 9, 8, 6, 45
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DISTRIB
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MEAN
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MEDIAN
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MODE
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SD
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RANGE
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a.
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b.
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c.
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d.
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2. Answer the following questions:
a. Why is the SD in (d) so large compared to the SD in (b)?
b. Why is the mean so much higher in (d) than in (b)?
c. Why is the median relatively unaffected?
d. Which measure of central tendency best represents the set of scores in (d)? Why?
3. Fill in the blanks on the table with the appropriate raw scores, z-scores, T-scores, and approximatepercentile ranks. You may refer to the distribution curve below.
Note: the Mean = 50, SD = 5.
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RAW
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z
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T
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Percentile
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35
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1.2
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35
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16
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4. The Graduate Record Exam (GRE) has a combined verbal and quantitative mean of 1000 and a standard deviation of 200. Scores range from 200 to 1600 and are approximately normally distributed. For each of the following problems:
(a) Indicate the percentage or score called for by the problem.
(b) Select the appropriate distribution curve (from below) that relates to the problem.
a. What percentage of the persons who take the test score above 1300? _______
Select the curve best representing your answer: _______
b. What percentage of the persons who take the test score above 800? _______
Select the curvebest representing your answer: _______
c. What percentage of the persons who take the test score below 1200? _______
Select the curve bestrepresenting your answer: _______
d. Above what score do the top 20% of the test-takers score? _______
Select the curve bestrepresenting your answer: _______
e. Below what score do the bottom 16% of the test-takers score? _______
Select the curve best representing your answer: _______
5. Refer to the following data and scatterplots to respond to questions 5a-5f.
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Individual
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Score on political awareness test
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Score on current events test
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1
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24
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23
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2
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16
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12
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3
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11
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11
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4
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9
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6
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5
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8
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13
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6
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14
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11
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7
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17
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16
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8
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19
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16
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9
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21
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21
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10
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25
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25
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11
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18
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11
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12
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13
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13
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13
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11
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14
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14
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6
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10
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15
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9
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10
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16
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12
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7
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Figure A represents a scatterplot constructed from the data; Figure B represents a regression line drawn through the scatterplot that "fits" the data points reasonably well; Figure C represents an ellipse drawn around the data points
a. Estimate the direction of the correlation: ________________________
b. Estimate the strength of the correlation coefficient:__________________
c. Consider Figure D (below), and use only the data points associated with current event scores of 15 and lower; what effects does this have on the direction and strength of the correlation coefficient?
d. Explain why this is the case.
e. Explain in words what a non-truncated scatterplot means.
f. Identify how likely it is that a causal relationship has been indicated.