9.3 Measures of Regression and Prediction Intervals

9.3 Measures of Regression and Prediction Intervals

Multiple Choice

Which statement below might be caused by the statement, "The more the furnace runs, ...."?

• the less time individuals spend outside.

• the longer you will have to let your car heat up when you start in the morning.

• the colder it is outside.

• the warmer the house becomes.

Multiple Choice

Which example shows CAUSATION?

• High social media usage and reduced grades.

• Car ran out of gas and being stranded on the side of the road.

Multiple Choice

Is it Correlation or Causation?

The amount of cars a salesperson sells and how much commission she makes.

• Correlation

• Causation

Multiple Choice

Shown is a residual plot. Would a linear regression model of the data be most appropriate?

• YES
• NO

Multiple Choice

Which is TRUE?
I.  Random scatter in the residual plot indicates a linear model.
II.  If two variables are very strongly associated, then the correlation between them will be near 1 or -1.
III.  Small residual values (close to 0) indicate possible outliers.

• I only
• II only
• I and II only
• I, II and III

Multiple Choice

The equation of the best-fit line is
y(hat) = 1.3 + 0.73x.  What is the residual for the point (4, 7)?

• 2.78
• 3.00
• 4.00
• 4.22

Multiple Choice

How do you calculate a residual?

• Observed - Predicted
• Predicted - Observed
• find r²  in your TI-84
• find r in your Ti-84

Multiple Choice

What should a residual plot look like?

• "U" Shaped
• Upside down "U"
• Random
• Circle 

Multiple Choice

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

Multiple Choice

What kind of trend is shown from this scatter plot?

• positive correlation
• negative correlation
• none
• cannot be determind

Multiple Choice

What is the correlation value?

• .209
• .457
• .13
• .361

Multiple Choice

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)

Multiple Choice

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. 

Multiple Choice

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. 

Multiple Choice

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

• $600
• $200
• $1000
• $800

Multiple Choice

What type of association does this graph have?

• positive 
• negative
• none
• all of the above

Multiple Choice

The points in the scatterplot represent paired observations (x, y) where x is an individual’s weight and y is the time (in seconds) it takes for walking on a treadmill to raise the individual’s pulse rate to 140 beats per minute. The open circles correspond to females and the dark squares to males.

• There is a positive correlation r between gender and weight, since men tend to weigh more than women.

• There is a negative correlation r between weight and time for both males and females.

• In general, males tend to take less time to have their pulse rate raised to 140 bpm while walking on the treadmill.

Multiple Choice

The points in the scatterplot represent paired observations (x, y) where x is an individual’s weight and y is the time (in seconds) it takes for walking on a treadmill to raise the individual’s pulse rate to 140 beats per minute. The open circles correspond to females and the dark squares to males.

• There is a positive correlation r between gender and weight, since men tend to weigh more than women.

• There is a negative correlation r between weight and time for both males and females.

• In general, males tend to take less time to have their pulse rate raised to 140 bpm while walking on the treadmill.

Multiple Choice

You are analyzing a scatter plot that has a negative correlation. What is true of the of the x and y values?

• As x increases, y decreases

• As x increases, y increases

• As x decreases, y decreases