Does a person's height relate to their arm span? We will attempt to answer this question in the following project.
1) Collect data from 15 people. Measure each person's height (in inches) and then their arm span (in inches), which would be from finger tip to finger tip as they hold their arms outstretched.
Record your results in a table similar to the one below. Your results will be more generalized if you collect data from people of many different heights, from children to tall men.
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Height (in)
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Arm Span (in)
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(This should be a table with two rows and fifteen columns for each of your entries.)
2) Create an accurate scatter plot of the data. This can be done by hand or using a program like Excel. Use Height as the x variable and Arm Span as the y variable. Does this graph show a linear relationship between x and y?
3) Calculate the correlation coefficient, r and list it on your project. You may use the formula in the book, your calculator, or Excel.
4) Calculate the equation of the regression line, using your calculator or Excel. Draw the regression line on your scatter plot either by hand or using Excel and report the equation as part of your project.
5) What is the relationship between a person's arm span and height? (Use a sentence or two to accurately describe the relationship.)
6) Now, collecting data from the same 15 people, measure each person's height and arm span in cm and record in a table similar to the one below. Do NOT just use a formula to change inches into centimeters - actually measure in centimeters!
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Height (cm)
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Arm Span (cm)
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7) Calculate the correlation coefficient, r, for the data in cm and list it on your project.
8) How does the r-value from #3 compare to the r-value in #7? Explain in detail the reason for this similarity or difference.