Correlation and Predictions of Linear Functions

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.  Use the equation to predict how far this person will travel after 10 hours of driving.

• 10 miles
• 617.5 miles
• 0.19 miles
• 500 miles

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.

A restaurant sells pizza for the prices in the data table.  Calculate the linear regression equation of the data.

• y = 1.5x + 12
• y = 12x + 1.5
• y = 0.67x - 8
• y = -8x + 0.67

• 5,000
• 2,620
• 17,000
• 20,200

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

A person travels by car.  They record their miles driven in a data table.  Calculate the linear regression equation of this data.

• y = 61.93x - 1.79
• y = -1.79x + 61.93
• y = 0.016x + 0.03
• y = 0.03x + 0.016

The annual profits for a company are given in the following table, where x represents the number of years since 1992, and y represents the profit in thousands of dollars. Write the linear regression equation that represents this set of data, rounding all coefficients to the nearest hundredth. Using this equation, estimate the year in which the profits would reach 378 thousand dollars.

• 2029

• 2014

• 2003

• 8753

The number of newly reported crime cases in a county in New York State is shown in the accompanying table, where x represents the number of years since 1994, and y represents number of new cases. Write the linear regression equation that represents this set of data, rounding all coefficients to the nearest hundredth. Using this equation, find the projected number of new cases for 2003, rounded to the nearest whole number.

• 974

• 25,101

• 940

• 952

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

• $600
• $200
• $1000
• $800