Predicting Heights

Predicting Heights Jimmy L. Colleen M. Brandon D.

What we measured • Middle Finger • We measured from the from the knuckle to the tip of the middle finger • Recorded that measurement to the nearest 8th inch • Possible bias: nail length • Forearm Length • We measured from the elbow to the very end of the forearm or the start of the wrist • Recorded that measurement to the nearest 8th inch • Possible bias: misjudging where the forearm ends • Wrist Circumference • We measured the circumference of the wrist from the point just below where your thumb joins your hand • We recorded that measurement to the nearest 8th inch • Possible bias: measuring in the wrong place, bracelets that may have gotten in the way

Middle Finger • Scatter Plot: Positive, linear, weak • R2 -14% of the change in height can determined by the change in middle finger length

Wrist Scatter Plot: Positive, moderately weak, linear R2 - 27% of the change in height can be determined from the change in wrist circumference

Forearm Scatter Plot: Positive, Moderate, linear R2 - 47% of the change of height can be determined by the change is forearm length

Middle Finger: Gender • Females: have a higher y-intercept but a smaller slope • R = .44 • Weak Scattered • Males: have a lower y-intercept but a higher slope • R = .10 • Weak Scattered

Wrist: Gender • Females: Higher y-intercept but lower slope • R = .31 • Weak Linear • Male: Lower y-intercept but higher slope • R = .24 • Weak Scattered

Forearm: Gender • Females: have a lower y-intercept but a higher slope. • R = .16 • Weak linear • Males: have a higher y-intercept but a lower slope. • R = .54 • Weak Linear

And the winner is… • Forearm length was chosen as our best model because… • The residual plot is scattered • With an r = .687, it has the highest correlation • 47% of the change in height can be determined by the change in the length of the forearm

Predicting our heights • Jimmy • Forearm length = 10.5 • 3.62(10.5)+32.1=Height • Height = 70.11 inches • Actual Height = 69.5 inches • Residual = -.61inches • Colleen • Forearm length = 9.5 inches • 3.62(9.5)+32.1=Height • Height = 66.49 inches • Actual Height = 64 inches • Residual = -2.49 inches • Brandon • Forearm length = 10.25 • 3.62(10.25)+32.1=Height • Height = 69.205 inches • Actual Height = 71 inches • Residual = 1.795 inches

Predicting the teachers • Ms. Wilson • Forearm length = 10 inches • 3.62(10)+32.1=Height • Predicted Height = 68.3 inches • Mrs. Robinson • Forearm length = 10 inches • 3.62(10)+32.1=Height • Predicted Height = 68.3 inches • Ms. Arden • Forearm length = 9 inches • 3.62(9)+32.1=Height • Predicted Height = 64.68 inches • Mr. Smith • Forearm length = 11 inches • 3.62(11)+32.1=Height • Predicted Height = 71.92 inches We are somewhat confident in our predictions because even though this model had the highest correlation out of all of the others, its strength is still only moderate

Bias/Error • Not measuring the same for everyone • Not knowing where to call the measurement from

Conclusion • Best body part to predict height would be the forearm (based on our data) • How you measure can change your data

Predicting Heights