Chapter 3, Problem 2CRE

(a)

To determine

To describe: the direction, form, and strength of the scatterplot.

Answer to Problem 2CRE

Direction: positive

Form: slightly curved

Strength: moderately strong.

Explanation of Solution

Given:

  

Calculation:

The graph shows a clear direction: the overall pattern moves from lower left to upper right. That is, animals having higher gestation period tend to have higher life span. This is a positive association between the two variables. The form of the relationship is slightly curved. The overall relationship is moderately strong: animals with similar gestation period tend to have roughly similar life span.

Conclusion:

Direction: positive

Form: slightly curved

Strength: moderately strong.

(b)

To determine

To find: In what way the animals are "unusual”

Answer to Problem 2CRE

Point A: unusual because of its high life span.

Point B: unusual because of the combination of a long gestation period and a low life span

Point C: unusual because of its high life span and its long gestation period

Explanation of Solution

Three animals stand out in the scatterplot: point A is for the hippopotamus, point B is for the giraffe, and point C is for the Asian elephant. These points can be described as outliers since they fall outside the overall pattern.

Point A: unusual because of its high life span.

Point B: unusual because of the combination of a long gestation period and a low life span

Point C: unusual because of its high life span and its long gestation period