A real good probability question?

Question

When bears were anesthetized, researchers measured the distance (in inches) around their chests and they weigher the bears (inpounds). Based on the results, does a bear's weight seem to be related to its chest size? Do the results change if the chest measurements are converted to feet? ( you need to determine r)

X Chest (in.), Y Weight (lb.) (X,Y) 26,90; 45,344; 54,416; 49,348; 41,262; 49,360; 44,332; 19,34

Is there a linear corielation? How strong? Positive or Negitive correlated? Predict the weight of a bear whose chest measures 30 in.?

Answer 1

I forget how to compute "r," which you need to tell how strong the relationship is, but there is a positive linear correlation. If you have a TI-83, you can put the X data in L1 and Y in L2. Go to 2nd-->StatPlot (above Y= button) and make sure your x-axis = L1(X data) and y-axis = L2(Ydata). You can then compute a Least Squares Regression Line, which is y=11.27125015157x - 187.46234994542 (y = mx +b). When a bear has a chest measurement (X)of 30 in., they prjected weight (Y) would be 150.67lbs. The site below will help with the strength of r.

http://helios.bto.ed.ac.uk/bto/statistics/tress11.html

Answer 2

You can find the correlation coeff on the TI-83. Once you do the fit:

This is where variables related to the statistics functions are stored:

VARS->STAT -> (then look around, you find the coeffs, n, r somewhrere.

Answer 3

You lost me.