Linear Correlation and Regression

The correlation coefficient measures...

• whether there is a relationship between two variables.

• the strength of the relationship between two quantitative variables.

• whether a cause and effect relation exists between two variables.

• the strength of the linear relationship between two quantitative variables.

What letter do we use to represent correlation coefficient?

• c

• r

• p

• h

Which scatter plot shows no relationship?

• Graph A

• Graph B

• Graph C

• Graph D

What would be the correlation be between the "number of times a student skips class" and their "exam score"?

• positive correlation

• negative correlation

• no correlation

• cannot be determined

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

Describe the correlation in the graph shown.

• Strong Negative

• Strong Positive

• Weak Negative

• Weak Positive

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 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

If x is temperature and y is coffee sales, use the following formula to determine the coffee sales on a 34° day.

y = -60x+6443

• $4403

• $4673

• $8483

• $6443