Questions 3–5 refer to the following information.
The first metacarpal bone is located in the wrist. The scatterplot below shows the relationship between the length of the first metacarpal bone and height for 9 people. The line of best fit is also shown.
Based on the line of best fit, what is the predicted height for someone with a first metacarpal bone that has a length of 4.45 centimeters?
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Choice C is correct. Students must see that the scale of the x-axis is 0.1, and therefore the x-value of 4.45 is halfway between the unmarked value of 4.4 and the marked value of 4.5. The student must then find the y-value on the line of best fit that corresponds with an x-value of 4.45, which is 170.
Choice A is not the correct answer. A student who mistakenly finds the point on the line between the x-values of 4.3 and 4.4 will find a predicted metacarpal bone length of 168 centimeters.
Choice B is not the correct answer. A student who mistakenly finds the point on the line that corresponds with an x-value of 4.4 centimeters will find a predicted height of approximately 169 centimeters.
Choice D is not the correct answer. A student who mistakenly finds the point on the line that corresponds with an x-value of 4.5 centimeters will find a predicted height of approximately 171 centimeters. Students might also choose this option if they mistakenly use the data point that has an x-value closest to 4.45 cm.
Students must use the line of best fit to make a prediction. Students must also demonstrate fluency in reading graphs and decimal numbers.