For women, pregnancy lasts about 9 months (278 days). In other species of animals, the length of time from conception to birth varies. A biologist wants to use life expectancy to predict gestation period. Given below are the life expectancy (in years) and the gestation period (in days) for 18 species of mammals.

Anima / l Life Expectancy in Years / Gestation in days

Ass / 19 / 365

Cat 11 63

Cow 10.5 280

Dog 11 62

Elephant 35 624

Fox 9 57

Goat 12 151

Guinea Pig 3 88

Hamster 2 16

Hippo 30 240

Horse 22.5 336

Lion 10 108

Human 81 278

Pig 10 115

Rabbit 7 31

Sheep 12 151

Squirrel 8.5 44

Wolf 11 61

b) Find the slope and y-intercept of the regression line.

Slope = ________________________ y-intercept = ___________________________

c) What is the equation of the regression line in this problem?___________________________

e) What does the value of the slope tell you about the relationship life expectancy and gestation period for mammals?

f) What is the value of r? Explain what the value tells you about the relationship between life expectancy and gestation period.

r =_____________________

h) Is there reasonable justification for removing humans from the data set?

j) What is the slope of the new line for nonhuman species? What is the y-intercept of the new line? Slope = ___________________________ y-intercept = _____________________________

k) What is the regression line for nonhuman species? _____________________________

m) What is the value of r for the new line using the 17 nonhuman species?

For the nonhuman species, r = ____________________

n) Some species of monkeys have a life expectancy of about 20 years. What is the predicted gestation period of one of these monkeys? Round your answer to the hundredths place.

o) Compare the r value for the original regression analysis which included humans to the regression using only nonhuman species. Which set of data indicates a stronger linear relationship between life expectancy and gestation period?

p) Do you think that humans were an outlier? Do you think humans were an influential observation?