Scatterplots and Regression

The ages (in years) and the number of hours of sleep in one night for 7 adults is shown. Given y = -0.09x + 10.45, The actual hours of sleep for someone who is 62 is 6 hours. Calculate and interpret the residual.

• 13, The model predicted 1.13 more hours of sleep than the actual sleep.

• 1.13, The model predicted 1.13 fewer hours of sleep than the actual hours of sleep.

• -1.13, The model predicted 1.13 fewer hours of sleep than the actual hours of sleep.

• -1.13 The model predicted 1.13 more hours of sleep than the actual hours of sleep.

What is the definition of a residual?

• A residual is the difference between the actual y values and predicted y values.

• A residual is the difference between the actual x values and the predicted x values.

• A residual is the percent of variation in y accounted for by the linear model with x.

• A residual determines the strength and direction of a linear relationship.

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

Which graph shows a line of best fit for the scatter plot?

• Graph A

• Graph B

• Graph C

• Graph D

Estimate the correlation coefficient for this scatterplot.

• r = 1.2

• r = 0.89

• r = 0

• r = -0.89

What type of association does this graph have?

• positive 

• negative

• none

• all of the above

As x increases, y decreases.

• no correlation

• negative correlation

• correlation coefficient

• positive correlation

Find the slope for the trend line using points (2,2) and (4,3)

• 2

• 1/2

• -2

Which statement best describes the relationship shown in this scatter plot?

• Students with a bigger shoe size earn a higher math score

• Students with a smaller show size earn a higher math score

• A student's shoe size has no effect on their math score

• A student with a shoe size of 8 will always earn a score of 80%

Which with is the line of best fit?

• Black

• Orange

• Red

• Blue