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07-09-2019, 08:17 PM
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#1
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Senior Member
Name: Justus
Trailer: Currently Shopping
California
Posts: 291
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Casita and Scamp Used Sales Data
Hello everyone. A few months ago I wrapped up a statistics class. The class required a final project using student-generated data. I chose to look at sales info from used Casitas and Scamps. I collected data from 73 Scamp 16 ads and 233 Casita 16/17 ads entirely from fiberglass-rv-4sale.com because that was the easiest way to do it.
Maybe someone will find it useful, so I've uploaded the project to my Google Drive. I've included the spreadsheet where I did all my calculations as well as the writeup (yawn): https://drive.google.com/open?id=1yP...erQrLi0OlbLdvS
For the instant gratification types, trailers roughly followed these models:
Scamp 16: y = 8.0334x² - 597.59x + 17738 (R² = 0.6717)
Casita 17: y = 10.407x² - 764.92x + 20161 (R² = 0.7182)
Casita 16: y = 12.532x² - 831.04x + 20199 (R² = 0.7987)
Where y is the estimated asking price, and x is the age in years.
Bear in mind that this accounts for no options or trailer condition (although I threw out trailers that were advertised as gut-and-restore or unusable). It models a general trend among all trailers of the given brand and size.
There's more data manipulation in the report but my gut feeling is that most people who care about this type of data are looking for a price check.
And I do realize that by using a polynomial equation that if you put in an old enough trailer age, the price will be infinite. It was the best fit for the data range I had. For ages 20 and up, they are pretty darn accurate. Nobody's perfect!
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07-09-2019, 09:37 PM
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#2
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Senior Member
Name: John
Trailer: Hymer
California
Posts: 200
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Did you get an A?
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07-10-2019, 06:58 AM
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#3
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Senior Member
Name: Justus
Trailer: Currently Shopping
California
Posts: 291
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Quote:
Originally Posted by OCJohn
Did you get an A?
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Yes!
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07-10-2019, 10:48 AM
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#4
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Senior Member
Trailer: No Trailer Yet
Posts: 1,704
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I would have died from boredom having to create that. Thank God for people He's provided to do such stuff so I can sit back and enjoy life!
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07-10-2019, 11:04 AM
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#5
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Junior Member
Name: Steven
Trailer: Rockwood
Kentucky
Posts: 3
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Used sales data
Just cut to the chase- I hated Algebra! In plain English, what were your findings?
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07-10-2019, 11:07 AM
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#6
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Senior Member
Name: Henry
Trailer: BigFoot
Tennessee
Posts: 1,312
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I have a 2013 Casita Spirit Deluxe I expect to put on the market after this camping season. According to your formula, an asking price of $15,946.13 would be reasonable.
In my case I would add $2k for a gas Honda eu3000is generator with remote, and many other modifications, with a value of say $1k.
So an asking price of $18,946 should be about right. Are my calculations correct, based on your formula?
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07-10-2019, 12:58 PM
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#7
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Junior Member
Name: David
Trailer: Oliver
Utah
Posts: 25
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Hi Justus,
As an academic (but not a statistician) I really liked your regression analysis and the strong correlation on price vs age.
I have several questions.
Could you do a similar regression analysis on price vs distance from the factory? I would expect that Casitas far from Rice TX would have a higher resale value.
Could you determine how much the absence of a bathroom affects the price? I see you have less than a dozen trailers without a bathroom, and that could be too small of a sample size.
I have often wondered how many of each brand of fiberglass trailer have been sold are on the road. I recently took the data from the Tow Vehicle & Trailer Combos thread (n = 199) and found 24% were Scamps and 18% were Casitas. Tongue in cheek, I posted that "Of course, it is possible that Scamp owners are simply more likely to respond to a survey like this..."
http://www.fiberglassrv.com/forums/f...tml#post747885
Quote:
Originally Posted by Justus C
I collected data from 73 Scamp 16 ads and 233 Casita 16/17 ads entirely from fiberglass-rv-4sale.com because that was the easiest way to do it.
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However, you found three times as many ads for Casita as for Scamps. Why the difference?
Thanks.
__________________
David from Salt Lake City, UT
Oliver Elite II Trailer
Audi Q7 Tow Vehicle
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07-10-2019, 02:15 PM
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#8
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Senior Member
Name: Justus
Trailer: Currently Shopping
California
Posts: 291
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Quote:
Originally Posted by salmiddleton
Just cut to the chase- I hated Algebra! In plain English, what were your findings?
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I hate algebra too but in this case the calculator (and the computer) did most of the legwork. The back cover edition is: No significant different in depreciation; no correlation between location and price; most trailers have bathrooms; distance from the factory has some effect on price (not a direct positive correlation); most trailers sleep three; at least 85% sleep 2 to 4; at least 5% of used Casitas and Scamps sold are 30 years old or more; and the equations I came up with were useful.
Quote:
Originally Posted by Rzrbrn
I have a 2013 Casita Spirit Deluxe I expect to put on the market after this camping season. According to your formula, an asking price of $15,946.13 would be reasonable.
In my case I would add $2k for a gas Honda eu3000is generator with remote, and many other modifications, with a value of say $1k.
So an asking price of $18,946 should be about right. Are my calculations correct, based on your formula?
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I would use the formulas for entertainment purposes only. Although they give a ballpark price, that is not necessarily what you could or should sell/buy at. A thing is worth whatever someone will pay for it.
One thing I just lost the motivation to do was account for seasonal variation in price. For example, right now, at the height of camping season, trailers may sell for a little more than in September. I can check FGRV4Sale and see that a 2013 Liberty Deluxe sold recently for $17,300. But if I go back to January, I can find a 2013 Spirit Deluxe that sold for $16,250, and in March one that sold on eBay for $14,500. You can filter my spreadsheet results to see only 2013 Casitas, and even further to see only 2013 Casita Spirit Deluxe 17s if you wish.
And as mentioned, I had some other shortcomings. The goal of the project was to demonstrate an understanding of various hypothesis tests and basic statistics, but a convenient side effect was that I could generate price models.
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07-10-2019, 02:26 PM
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#9
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Senior Member
Name: Justus
Trailer: Currently Shopping
California
Posts: 291
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Quote:
Originally Posted by DavidJS
Hi Justus,
As an academic (but not a statistician) I really liked your regression analysis and the strong correlation on price vs age.
I have several questions.
Could you do a similar regression analysis on price vs distance from the factory? I would expect that Casitas far from Rice TX would have a higher resale value.
Could you determine how much the absence of a bathroom affects the price? I see you have less than a dozen trailers without a bathroom, and that could be too small of a sample size.
I have often wondered how many of each brand of fiberglass trailer have been sold are on the road. I recently took the data from the Tow Vehicle & Trailer Combos thread (n = 199) and found 24% were Scamps and 18% were Casitas. Tongue in cheek, I posted that "Of course, it is possible that Scamp owners are simply more likely to respond to a survey like this..."
http://www.fiberglassrv.com/forums/f...tml#post747885
However, you found three times as many ads for Casita as for Scamps. Why the difference?
Thanks.
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David, bear in mind that I only used one source for sales data. It could be that FGRV4Sale is just way more popular with Casita owners. It could be that Casitas change hands more often than Scamps. It could be, as you said, that Scamp owners are more likely to respond to such a survey. It could be that there is a bias of Scamp owners on this site. The universe holds many mysteries! I believe that Scamp production numbers are significantly lower than Casita numbers, though, so I would expect to see more Casita sold on the used market.
I was also curious about the bathroom, but as you noted, the sample of non-bathroom models was tiny. If there was enough data, you could run a 2 Sample T-Test where the variable is the difference between average price with and without a bathroom.
The distance data was difficult to work with. I really wanted to generate a heat map of price by actual location but not only was this beyond the scope of the project--I couldn't even figure out where to start! On page 11 of the writeup I categorized distances and ran a chi-square test, then built a nearly-impossible-to-read line graph. It's shows a correlation, but not what you might expect.
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07-11-2019, 08:14 PM
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#10
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Member
Name: MJ
Trailer: Park Liner
GA
Posts: 60
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No Park Liner data collated? Where are all these folks? Am I all alone? ...Hello? ... Is anyone there? (I hear crickets)
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07-12-2019, 08:42 AM
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#11
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Senior Member
Name: Jon
Trailer: 2008 Scamp 13 S1
Arizona
Posts: 11,962
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Casita and Scamp Used Sales Data
@ Tinkerbelle: There wouldn’t be enough Parkliner sales data over enough years to get a reliable mathematical model. (Chirp, chirp...)
Good work, Justus! Fun project. One bone to pick... why not Scamp 13’s? They’re Scamp’s most popular model.
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07-12-2019, 11:01 AM
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#12
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Senior Member
Name: Mike
Trailer: Escape 21 & Jeep GC 5.7 (Previous 2012 Casita FD17 & 2010 Audi Q5)
Puget Sound, WA
Posts: 1,775
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Quote:
Originally Posted by Rzrbrn
I have a 2013 Casita Spirit Deluxe I expect to put on the market after this camping season. According to your formula, an asking price of $15,946.13 would be reasonable.
In my case I would add $2k for a gas Honda eu3000is generator with remote, and many other modifications, with a value of say $1k.
So an asking price of $18,946 should be about right. Are my calculations correct, based on your formula?
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For what it may be worth, this was compiled in August of 2017 based on data from the same site. It includes 86 Casita Deluxe trailers. Seven are 16 ft, the rest are 17 ft. They are a mix of 49 Spirit, 18 Freedom, 13 Liberty, 4 Independence and 2 uncertain.
__________________
~ “It’s absurd to divide people into good and bad. People are either charming or tedious.” Oscar Wilde ~
~ “What the human being is best at doing is interpreting all new information so that their prior conclusions remain intact.” Warren Buffett ~
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07-12-2019, 11:04 AM
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#13
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Senior Member
Name: Mike
Trailer: Escape 21 & Jeep GC 5.7 (Previous 2012 Casita FD17 & 2010 Audi Q5)
Puget Sound, WA
Posts: 1,775
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Quote:
Originally Posted by Justus C
And I do realize that by using a polynomial equation that if you put in an old enough trailer age, the price will be infinite. It was the best fit for the data range I had. For ages 20 and up, they are pretty darn accurate. Nobody's perfect!
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__________________
~ “It’s absurd to divide people into good and bad. People are either charming or tedious.” Oscar Wilde ~
~ “What the human being is best at doing is interpreting all new information so that their prior conclusions remain intact.” Warren Buffett ~
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07-12-2019, 01:02 PM
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#14
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Senior Member
Name: Justus
Trailer: Currently Shopping
California
Posts: 291
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Quote:
Originally Posted by Jon in AZ
Good work, Justus! Fun project. One bone to pick... why not Scamp 13’s? They’re Scamp’s most popular model.
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It's quite simple: I would never consider buying a 13' Scamp! But I did recently recommend it to my parents as an ideal sub-2000 lbs full featured trailer.
I wanted two data sets to do all of the hypothesis testing required in the paper. The Scamp 16/Casita 16/17 pairing was the most convenient.
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07-17-2019, 09:01 AM
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#15
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Senior Member
Name: Henry
Trailer: BigFoot
Tennessee
Posts: 1,312
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Thanks Justus, I have really enjoyed this thread.
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07-17-2019, 12:19 PM
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#16
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Junior Member
Trailer: No Trailer Yet
Posts: 21
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Quote:
Originally Posted by Justus C
Hello everyone. A few months ago I wrapped up a statistics class. The class required a final project using student-generated data. I chose to look at sales info from used Casitas and Scamps. I collected data from 73 Scamp 16 ads and 233 Casita 16/17 ads entirely from fiberglass-rv-4sale.com because that was the easiest way to do it.
Maybe someone will find it useful, so I've uploaded the project to my Google Drive. I've included the spreadsheet where I did all my calculations as well as the writeup (yawn): https://drive.google.com/open?id=1yP...erQrLi0OlbLdvS
For the instant gratification types, trailers roughly followed these models:
Scamp 16: y = 8.0334x² - 597.59x + 17738 (R² = 0.6717)
Casita 17: y = 10.407x² - 764.92x + 20161 (R² = 0.7182)
Casita 16: y = 12.532x² - 831.04x + 20199 (R² = 0.7987)
Where y is the estimated asking price, and x is the age in years.
Bear in mind that this accounts for no options or trailer condition (although I threw out trailers that were advertised as gut-and-restore or unusable). It models a general trend among all trailers of the given brand and size.
There's more data manipulation in the report but my gut feeling is that most people who care about this type of data are looking for a price check.
And I do realize that by using a polynomial equation that if you put in an old enough trailer age, the price will be infinite. It was the best fit for the data range I had. For ages 20 and up, they are pretty darn accurate. Nobody's perfect!
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My complements on using a statistics assignment to generate some useful info for consumers. The correlation coefficients on the Casitas look very strong.
What was the standard deviation of the polynomial curve fits? The standard deviation should always be quoted for these types of analysis. This gives an indication of the precision of the curve fit to the data. the correlation coefficients imply this but a user can apply the standard deviation as +/- so many dollars
One comment. The y intercept for x =0 for a Casita 17 ft is $20161. Similarly the Casita 16 intercept is $20199. I would have expected a greater difference with the higher number for the 17 footer.How do these square with the average new price? Using the factory new price as a data point may change the curve fit or even the degree of the polynomial.
These are not meant to be critical of your work, merely observations from one who has done statistical analysis in his professional career.
Once again, thanks for doing this
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07-17-2019, 05:39 PM
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#17
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Member
Name: Mike
Trailer: Featherlite
Iowa
Posts: 37
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Quote:
Originally Posted by Justus C
Hello everyone. A few months ago I wrapped up a statistics class. The class required a final project using student-generated data. I chose to look at sales info from used Casitas and Scamps. I collected data from 73 Scamp 16 ads and 233 Casita 16/17 ads entirely from fiberglass-rv-4sale.com because that was the easiest way to do it.
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In my opinion, the prices arent realistic because they are asking prices. A more accurate way is to look at ebays completed and sold listings for real world sales prices. I feel its a better resource than KBB etc.
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07-17-2019, 06:54 PM
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#18
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Senior Member
Name: Henry
Trailer: BigFoot
Tennessee
Posts: 1,312
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Yes, I think Mike has a good point.
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07-17-2019, 07:07 PM
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#19
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Junior Member
Trailer: Scamp 13 ft
Posts: 4
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Hey, great idea for a project! Congratulations on your A. Thanks for sharing.
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07-23-2019, 12:48 PM
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#20
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Junior Member
Name: Deb
Trailer: Casita
Indiana
Posts: 3
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Wow!
Thank you so much for posting this. What a great topic for a stats project.
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