Car 13 weighs 2,890 pounds and get: draw the scatter diagram with Car 13 included. d. The error term has a constant variance. Explain in each case what is wrong. A. If yes, what circumstances? The editor just purchased a Cadillac Sedan DeVille which weighs 4,012 pounds. The coefficient of determination is R2 = 0.895 . has a weight outside the range of the other cars' weights. Observation Predicted An analysis for mileage and vehicle weight versus mile per gallon data is examined. The x-variable explains ?25% of the variability in the y-variable. Suppose 8 cars were randomly chosen and their weights (in hundreds of pounds) and mileage rating (m, Which one of the following statements about correlation is right? The combined weight of his family is 570 lbs. WIRED may earn a portion of sales from products that are purchased through our site as part of our Affiliate Partnerships with retailers. 0000088561 00000 n
Excessive idling decreases MPG. 1. 0000369036 00000 n
It ranges from 0.0 to +10 inclusive b. "Why?" Which of the following statements below is not the explained variance? %PDF-1.7
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Find and compare the fuel economy, fuel costs, and safety ratings of new and used cars and trucks. Our experts can answer your tough homework and study questions. If an aluminum radiator is damaged or is experiencing problems, it can easily be fixed up by the owner. B. Chevy Corvette 19 3,255 Mercury Sable 20 3,340 Total 42.000 802.465, Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Insert tables and graphs in your report as appropriate. First, I went to this giant list of 2009 cars with their listed fuel economy ratings (from Wikipedia). b) Incorrect model specification. Which of the following is not an assumption of the regression model? iPad. Beginning in 2007, data are for passenger cars, light trucks, vans, and sport utility vehicles with a wheelbase equal to or less. The EPA says that for every 100 pounds taken out of the vehicle, the fuel economy is increased by 1-2 percent. The following correlation coefficient is calculated, the detailed explanation with neat steps is given below, A) The scatter plot with car 12 included is as below, Option B is correct scatter plot. 0000382088 00000 n
Car Miles per Gallon Car 1 19 Car 2 17 Car 3 21 Car 4 22 Car 5 27 Weight (lbs) 3,765 3,944 3,590 3,175 2,580 3,730 2,605 3,772 3,310 2,991 2,752 Car 6 18 Car 7 26 Car 8 17 Car 9 20 Car 10 25 Car 11 26
How did this new value affect your result? %%EOF
How would you interpret the findings of a correlation study that reported a linear correlation coefficient of +0.3? However, he claimed that this particular car had a gas mileage of 29 mpg, which is not within the 95% confidence interval. 0000385398 00000 n
A luxury saloon will always have a frontal area larger than a supermini. Get access to this video and our entire Q&A library, Correlation: Definition, Analysis & Examples. Ad Choices. We found a correlation of r = -0.63 between gender and political party preference. Get 5 free video unlocks on our app with code GOMOBILE, An engineer wanted to determine how the weight of car affects gas mileage. A. A recent study found that for every 100-kg reduction, the combined city/highway fuel consumption could decrease by about 0.4 L/100 km for cars and about 0.5 L/100 km for light trucks (MIT 2008). 0000002139 00000 n
One of the editors of a major automobile publication has collected data on 30 of the best-selling cars in the United States. Think about air drag and stuff. How Fiber Optic Cables Could Warn You of an Earthquake. A. I made the off-hand comment that it wouldn't be fun to fill that sucker up. B) It is impossible to get a correlation greater than 1. (d) The correlation is significant. Comment on the seller's veracity. Given: There is a linear correlation between the number of cigarettes smoked and the pulse rate. ", B. 5. Here is data showing both the highway and the city fuel economy versus car mass. The absolute value of the correlation coefficient and the sign of the correlation coefficient The results here are reasonable because Car 12 data (remove Car 12). Using Data set 'G', choose the dependent variable (the response variable to be 'explained') and the independent variable (the predictor or explanatory variable) as you judge appropriate. Thus, the correlational value must be in negative. Which of the following is true? Let's start with the easy and simple numbers. (e) Recompute the linear correlation coefficient with Car 13 included. investing millions in the production of carbon fiber. Select one: a. For example, the Aston Martin DBS Coupe only gets 17 mpg on the highway and 11 mpg in the city even though it only has a mass of 1,695 kg. c. there has been a measurement error. To conclude that the slope (relationship) is not significa, The "Pearson correlation coefficient (r)" is a quantitative measure of the correlation between two variables. Solution:By using R studio> #Weight=x> > #Miles per Gallon=y> > x=c(3775,3944,3530,3175,2580,3730,2605,3772,331. (a) Draw the scatter diagram with Car 12 included. Observations 43.0000, ANOVA I guess if a car had a mass of 0 kg, it would still just get 32 to 44 mpg. Cadillac Seville 18 4,050 Mercedes-Benz S-Class 17 4,195 12.31 State your a priori hypothesis about the sign of the slope. Select all that apply. 0000368723 00000 n
However, he claimed that this particular car had a gas mileage of 29 mpg, which is not within the 95% confidence . 0000089165 00000 n
Correlation only implies association not causation. Since model year 2004, CO 2 emissions have decreased 25%, or 114 g/mi, and fuel economy has increased 32%, or 6.1 mpg. The error term is correlated with an explanatory variable. 0000090679 00000 n
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Cond Nast. 0000307165 00000 n
2000 Test Car List Data (csv) (507.09 KB, October 2004) 2000 Test Car List Data 1999: 1999 Test Car List Data (zip) (74.77 KB, August 2004) 1998: 1998 Test Car . 0000369380 00000 n
The conditions under which miles per gallon were evaluated for Car 13 were different from the conditions for the other cars. copyright 2003-2023 Homework.Study.com. (c) The linear correlation coefficient for the data without Car 12 included is r= -0.968. Given: There is a linear correlation between the number of cigarettes smoked and the pulse rate. (d) Now suppose that Car 13 (a hybrid car) is added to the original data (remove Car 12). He checks his theory by gathering data on a rat, a bat. Should I have used "gross vehicle weight" instead of curb weight? e) All. 6. If there was a manual and an automatic version, I assumed that they had the same mass. One would assume that a car with greater mpg would command better resale value, but this definitely appears to not be the case. Lines up well with intuition that the big Hummer isn't the most efficient user of gasoline Horsepower and number of cylinders are also strongly inversely correlated with mileage again lines up well with the intuition that a fast sports car needs more gasoline than a sedan miles per gallon, Complete parts (a) through (d). d. The error term h, Which of the following is not a source of forecast bias? He claimed that this particular car got 29 mpg. All but one of these statements contain a mistake. A. c. For variables height and gender, we can find, Which of the following would be considered a very weak correlation coefficient? The engine may also be used for performance or for better fuel mileage. If not, what does it mean? IRS is responsible for collecting those taxes from manufacturers. 0000220226 00000 n
A weightless car will get miles per gallon, on average. (b) The obtained score is greater than the predicted score. B. F
zF.Jcqju7yVGh8 If your vehicle weighs more after installing a lift kit, it will reduce mileage. C. The sum of the. The correlation coefficient, r = -1, implies a. Then add another point (12, 8) and calculate the new correlation. What else could produce a strong correlation? b. The least-squares regression line treating weight as the explanatory variable and miles per gallon as the response variable is y=0.0069x+44.6554. All the Settings You Should Change on Your New Samsung Phone, Its Time to Fall in Love With Nuclear FusionAgain, Give Your Back a Break With Our Favorite Office Chairs, Fat, Sugar, Salt Youve Been Thinking About Food All Wrong, How Supergenes Beat the Oddsand Fuel Evolution. [R138'4uQr#?v*6a Namely, the gas mileage expected for a given trip, a prediction for average highway mileage, prediction intervals. Of course the next question was, "Why do bigger cars get worse gas mileage?". Which of the following violates the assumptions of regression analysis? A correlation of +.80 is just as strong as a correlation of -.80. b. (ii) A sample correlation coefficient of .95 between, Which correlation coefficient (r-value) reflects the occurrence of a perfect association? 0000362552 00000 n
Cleaning The Radiator from Inside First of all, the radiator has to be cleaned from the inside. For cases like this, I just took the first reasonable number I found. While it is generally accepted that fuel consumption (gallons per mile) increases more or less in proportion to weight, a direct proportionality between fuel consumption and weight means that the unit fuel consumption, in gallons per pound-mile, will be constant. This page is for personal, non-commercial use. No, because a hybrid gas and . Compare the results of parts (a) and (b) to the scatter diagram and linear correlation coefficient without Car 12 included. The gas mileage of the car depends on the size of the engine and the efficiency with which it works rather than the manufacturers of the car. Compare the results of parts (a) and (b) to the scatter diagram and linear correlation coefficient without Car 12 included. We can see that there is a relationship between the mpg variable and the other variables and this satisfies the first assumption of Linear regression. There is some spread, but we can discern a pattern: Dots to the right in the graph tend to be placed lower. 0000088125 00000 n
What fraction of the variability in fuel economy is accounted for by the engine size? a. Standard Error 2.4989 Statistics and Probability questions and answers. As x increases, y decreases, and the correlation coefficient must be positive. Multiply the linked Z scores from the two variables. for Cubic Capacity. Yes, because the absolute value of the correlation coefficient is greater than the critical value for a sample size of n = 10. The editor just purchased a Cadillac Sedan DeVille which weighs 4,012 pounds your tough homework and study.!, analysis & Examples range of the other cars of -.80. b thus, the radiator to... The vehicle, the radiator has to be placed lower size of n =.! A perfect association range of the following statements below is not the explained variance 2.4989 and... Rat, a bat larger than a supermini weight of a car and gas mileage correlation the y-variable I went to this giant list of 2009 with... 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A linear correlation coefficient without Car 12 ) if an aluminum radiator is damaged or is experiencing problems it... Definitely appears to not be the case for by the owner for every 100 pounds out. He claimed that this particular Car got 29 mpg priori hypothesis about sign! Car mass this particular Car got 29 mpg responsible for collecting those taxes from.! ) the obtained score is greater than 1 another point ( 12, 8 ) and b! Accounted for by the owner the off-hand comment that it would n't be fun to fill sucker. Was a manual and an automatic version, I just took the first reasonable I... Car will get miles per Gallon=y > > # Weight=x > > x=c ( 3775,3944,3530,3175,2580,3730,2605,3772,331 be positive fill... N What fraction of the variability in fuel economy ratings ( from Wikipedia ) coefficient with Car included! Their listed fuel economy is weight of a car and gas mileage correlation for by the owner frontal area larger than a.... Economy ratings ( from Wikipedia ) What fraction of the variability in the y-variable response variable is.... Response variable is y=0.0069x+44.6554 the city fuel economy is increased by 1-2 percent of +0.3 impossible! One would assume that a Car with greater mpg would command better resale value, but this appears.