Homework #5.6: Linear Regression Review1

If Joe worked 30 hours, how much is he expected to earn?

• $600
• $200
• $1000
• $800

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books.  Use the trend line to predict how many chapters would be in a book with 180 pages. 

• 12 chapters
• 15 chapters
• 18 chapters
• 21 chapters

Data was collected on the weight of a male  laboratory rat for the first 25 weeks after its birth. The linear regression equation is 
y= 40x+100, where x is number of weeks and y is weight in grams. 
What does the y-intercept mean in context of the problem?

• The predicted weight of the rat in year 0. 
• The predicted weight of the rat at birth. 
• The current weight of the rat. 
• The average increase in the rat's weight. 

The linear regression equation is y = 61.93x - 1.79.  According to the model, the slope can be interpreted as:

• After 0 hours of driving, they went 61.93 miles.
• They drove at a speed of 61.93 miles per hour.
• They drove 61.93 miles total.
• They drove 61.93 hours total.

Estimate the correlation coefficient for this scatterplot.

• A) r = -0.9

• B) r = 1

• C) r = 0.9

• D) r = -1

What type of correlation does this graph show?

• A) Positive

• B) negative

• C) none

• D) all of the above

A perfect positive correlation has a correlation coefficient of ____. 

• 1
• -1
• 0

Which scatter plot diagram shows the strongest positive correlation?

• 
• 
• 
• 

Which graph represents data that has a correlation coefficient close to -1?

• 
• 
• 
• 

The correlation coefficient, r is used to determine

• y values given values of x.

• x values given values of y.

• the strength and direction of relationship between x and y.

• none of these.