Regressions Workbook Answer Key
p. 537 # 9
a. scatter plot
b. exponential because the r value is better. (it also does not work for a log regression because
there is a value of x = 0)
c. y = 19.506 (1.027)x
d. y = .016x2 + .316x + 20.133
e. exponential: 50.898
quadratic: 52.245
p 542 #23
a. scatter plot
b. y = 199.00x + 23.93
c. skip
d. x = 31 (I did it as if you graduate in 2011); $6197.93
e. y = 926.184 (1.073)x
f. skip
g. x = 31 (I did it as if you graduate in 2011); $8227.88
h. exponential is better because the correlation coefficient is closer to 1
i. linear because the cost is lower
p. 542 #24
a. & b. scatter plot
c. y = 2.399x + 31.427
d. y = 55.417; it is very close to the actual height
e. 65.013
f. y = 2.263x + 32.688
g. girls because the value in front of the x (slope) is greater
h. 48.34; slightly less than the actual height
i. 79.644; no because at some point people stop growing, the average person does not grow
forever.