Review Questions
Complete the following exercises from “Review Questions” located at the end of each chapter and put them into a Word document to submit to the instructor.
Chapter 6, number 6.9
Indicate whether the following generalizations suggest a positive or negative relationship. Also speculate about whether or not these generalizations reflect simple cause-effect relationships.
a) Preschool children who delay gratification (postponing eating one marshmallow to win two) subsequently receive higher teacher evaluations of adolescent competencies.
b) College students who take longer to finish a test perform more poorly on that test.
c) Heavy smokers have shorter life expectancies.
d) Infants who experience longer durations of breastfeeding score higher on IQ tests in later childhood.
Chapter 7, number 7.8
Each of the following pairs represents the number of licensed drivers (X) and the number of cars (Y) for seven houses in my neighborhood:
DRIVERS (X) CARS (Y)
5 4
5 3
2 2
2 2
3 2
1 1
2 2
a) Construct a scatterplot to verify a lack of pronounced curvilinearity.
b) Determine the least squares equation for these data. (Remember, you will first have to calculate r, SSy, and SSx)
c) Determine the standard error of estimate, sy|x, given that n = 7.
d) Predict the number of cars for each of two new families with two and five drivers.
