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Session 7:
Homework
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Is there an association between the length of your forearm (elbow to wrist) and the length of your feet?
The following are measurements, in millimeters, for forearm length and right-foot length for 20 people:
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N = 20 measurements
Mean forearm length = 262.1
Mean foot length = 255.7 |
Scatter Plot
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Problem H1 |  |
Describe the association between forearm length and foot length.
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Problem H2 | |
Use the mean forearm length and the mean foot length to determine the quadrants and number of points in each quadrant.
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Problem H3 | |
a. | Use the quadrants from Problem H2 to create the contingency table for this data. |
b. | What percentage of people with above-average forearm lengths also have above-average foot lengths? |
c. | What percentage of people with above-average forearm lengths also have below-average foot lengths? |
d. | What percentage of people with below-average forearm lengths also have below-average foot lengths? |
e. | What percentage of people with below-average forearm lengths also have above-average foot lengths? |
f. | What do these percentages say about the strength of the association between forearm length and foot length? |
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Problem H4 |  |
Consider the line Foot Length = Forearm Length (YL = X).
a. | Complete the table below. |
b. | Determine the SSE for this data. |
When you click "Show Answers," the filled-in table will appear below the problem. Scroll down the page to see it.
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b. The SSE, (256 + 324 + ... + 400 + 1), is 3,374.
hide answers
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Problem H5 | |
Consider the line Foot Length = Forearm Length + 4 (YL = X + 4).
a. | Complete the table below. |
b. | Determine the SSE for this data. |
When you click "Show Answers," the filled-in table will appear below the problem. Scroll down the page to see it.
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b. The SSE, (400 + 196 +... + 576 + 25), is 4,558.
hide answers
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Problem H6 | |
Compare the SSE in Problem H4 with the SSE in Problem H5. Which line provides a "better" fit? Explain.
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