Arm Span Lab
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Arm Span Activity
 (Activity as described from SED Sample Tasks.)
Materials:  graphing calculator, tape measure or measuring device such as a yardstick, ruler.

Directions:
•  Stretch your arms as wide as you can.  Have someone measure the length, in inches, of your arm span from the tip of your fingers on one hand, across your back, to the tip of your fingers on your other hand.  Have the person also measure your height, in inches.  Place a ruler horizontally on the top of your head to indicate the location of your maximum height (as not to include the height of your hair.)  Now, measure your height.  Share this information with the class and aggregate all of the data.

•  Enter the information in two lists on your calculator.  In the first list, enter the heights, in inches, of all of the participants.  In the second list, enter the arm span, in inches, of all of the participants.

•  Make a scatter plot, where the independent variable is height, in inches, and the dependent variable is arm span, in inches.  What type of regression function would best model this data?  Explain your choice?

•  Write the regression equation with all constants rounded to the nearest tenth.  Using this equation, determine the arm span of a person who is 5 feet tall.  Using this equation, determine the arm span of a person who is 8 feet tall.  How reliable is this last prediction?  Explain.