Plants that grow on Swiss cliffs. Refer to the Alpine Botany

(Nov. 2012) study of rare plants that grow on the limestone cliffs of the Northern Swiss Jura mountains, Exercise 2.165

(p. 125). Data on altitude above sea level (meters), plant population size (number of plants growing), and molecular variance (i.e., the variance in molecular weight of the plants) LO9 

for a sample of 12 limestone cliffs are reproduced in the table.

Recall that the researchers are interested in whether either altitude or population size is related to molecular variance.

Cliff Number Altitude Population Size Molecular Variance 1 468 147 59.8 2 589 209 24.4 3 700 28 42.2 4 664 177 59.5 5 876 248 65.8 6 909 53 17.7 7 1032 33 12.5 8 952 114 27.6 9 832 217 35.9 10 1099 10 13.3 11 982 8 3.6 12 1053 15 3.2

a. Use simple linear regression to investigate the relationship between molecular variance (y) and altitude (x). Find and interpret the value of r2.

b. Use simple linear regression to investigate the relationship between molecular variance (y) and population size (x). Find and interpret the value of r2.

c. What are your recommendations to the researchers?