Linear Equation and Linear Regression

Students in a science class investigated how the speed of changes with the air temperature outside. The data is shown in the scatterplot. Based on the scatterplot, what is the best prediction of the speed of sound when the air temperate is 50 degrees C?

• 350 m/s

• 355 m/s

• 360 m/s

• 380 m/s

The scatterplot shows the average number of hours each of 13 people spends at work every week and the average number of hours each of them spends on recreational activities every week. Based on the scatterplot, what is the best prediction of the average number of hours a person spends at work every week if that person spends an average of 10 hours on recreational activities each week?

• 33 h

• 85 h

• 50 h

• 65 h

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

• $600

• $200

• $1000

• $800

Write the linear regression equation for the data set foot length (x) and height (y).

• y = 117.99 + 1.878x

• height^ = 28.39(foot length) + 1.155

• y = 1.878 + 117.99x

• height^ = 117.99 + 1.878(foot length)

Interpret the slope of the Least Squares Line Equation.

• Income increases by 31.45 with each additional hour worked.

• Income increases by 31.45

• As hours increases by one, income will increase by 31.45, on average

• As hours increases by one, income will increase by 31.45

Some data were collected on the weight of a male while laboratory rat for the first 25 weeks after its birth. The linear regression equation is weight^=100 + 40(time). Which is the best description of the slope for this regression equation in context of the problem?

• The slope of the line of regression is the time since birth of the rate. It demonstrates the predicted weight of a laboratory rate after so many months since birth.

• The slope is 40 grams/week which means the mouse gains about 40 grams per week after birth.

• The slope is 40 and it means for every increase in weeks the graph will increase. 

• The slope is 40, which tells us the line increases. 

Which is the best description of the y - intercept for the linear regression equation of the rats: weight^ = 100 + 40(time)?

• The y-intercept is 100 which means the rat is predicted to weigh 100 grams at birth. 

• The y-intercept is 100, which is where the graph crosses the y-axis. 

• 100 is where the data starts on the y-axis. 

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

• $600

• $200

• $1000

• $800

What is the correlation value?

• .209

• .457

• .13

• .361