Correlation Coefficient and Regression Lines

Data is analyzed comparing hours studied and grades. It is determined that the correlation coefficient is 0.92. What does this mean?

• There is a strong positive correlation between studying and grades.

• There is a strong negative correlation between studying and grades.

• There is a weak positive correlation between studying and grades.

• There is a weak negative correlation between studying and grades.

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

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

• A plane ride costs $0.136 (13 cents)

• For every 1 mile flown, the cost goes up  $ 0.136 dollars (13 cents)

• For every 1 mile flown, the cost goes up $74

• $7.60

• $5.60

• $7.50

• $4

• m is 2.95

• Mr. Fisher has to spend $4.95

• For every 1 roomate who wants ice cream, the cost goes up $2.95.

• For every 1 roommate who wants ice cream, the cost goes up $4.95

Estimate the correlation coefficient for this scatterplot.

• A) r = 1.2

• B) r = 0.89

• C)r = 0

• D) r = -0.89

What kind of correlation?

• Positive
• Negative
• No

What kind of correlation?

• Positive
• Negative
• No