car study & statistics
DESCRIPTION
Presentation on hypothesis of fuel efficiency of international cars and American cars.TRANSCRIPT
• Collect data on price of new cars in local area
• Visit several dealerships & target 30-40 cars
• Gather variables:
•Record prices, model, type, & average mileage
• Make hypothesis, correlation, & summary based on information obtained
•Analyze information obtained & perform calculations
• cross section – tracked several units (cars) at one point in time (specifically 2007)
• disaggregate level – individual cars that make up aggregate
• discrete – fixed number value (price)
The higher the MPG, the less expensive the car is
• Average of 1.9 automobiles per household in U.S.
• Automobiles are staple for transportation
• Cars are expensive!
• Analyzing how MPG affects price can help make people make better economical & intelligent decisions when purchasing vehicles
• Secondary data – gathered from websites
• www.fueleconomy.gov • For highway gas mileage
• http://www.colonialnj.com/ •1655 North Olden Avenue Trenton, NJ 08638.
•http://www.haldemancar.com/ •607 Highway 33 Hamilton Square, 08619
•http://www.bobmaguirechevrolet.com/en_US/ • Bob Maguire Chevrolet 840 US Highway 206 Bordentown, NJ 08505
•http://www.lakewoodtoyota.com/ou/lakewood-toyota/?make=toyota •1118 Ocean Ave.
Route 88 Lakewood, NJ 08701•http://www.haldemannissan.com/en_US/
•951 US Highway 33 Hamilton Square, NJ 08690
• Minimum MPG: 18
• Lower Quartile: 20
• Median: 22.5
• Upper Quartile: 27
• Maximum MPG: 34
• Mean MPG: 23.73
• Standard Deviation MPG: 4.2
• Therefore, most data is between 19.53 and 27.93
• (Except for outliers)
• Variance of MPG: 17.7
• Gives better understanding of % of info falls under certain category
• MPG of 25+ is 13/30.
• MPG of 25 & cost more than $25,000 is 5/13 – very small considering the average cost of a
new car in America is $27,958, according to USA today in 2005.
Histo g ra m
Co m p a n ie s
Fo rdCa d i l l a c
Hyu n d a iM i tsu b i sh i
Ch e vro le tT o yo ta
Ni ssa n
Co m p a n y Na m e s
0
1
2
3
4
5
6
7
8
No
of
ob
s
Histo g ra m (S p re a d sh e e t1 1 0 v*3 2 c)
M P G = 3 0 *1 .6 *n o rm a l (x, 2 3 .7 3 3 3 , 4 .2 0 9 5 )
1 8 .0 1 9 .6 2 1 .2 2 2 .8 2 4 .4 2 6 .0 2 7 .6 2 9 .2 3 0 .8 3 2 .4 3 4 .0
M P G
0
2
4
6
8
1 0
1 2
No
of
ob
s
Conclusion based on observation of histogram: Slightly right skewed
Mean is to the right of the median – mean 22.73 > median 22.5
Histo g ra m
Ca r Co sts
1 0 0 0 0 1 5 0 0 0 2 0 0 0 0 2 5 0 0 0 3 0 0 0 0 3 5 0 0 0 4 0 0 0 0 4 5 0 0 0 5 0 0 0 0 5 5 0 0 0 6 0 0 0 0 6 5 0 0 0
Co st i n Do l l a rs
0
1
2
3
4
5
6
7
8
9
No
of
ob
s
Slightly right-skewed
B o x P lo t M P G b y T yp e
M e d i a n 2 5 % -7 5 % No n -O u tl i e r Ra n g e O u tl i e rs E xtre m e s
ca r S UV T ru ck
T yp e
1 6
1 8
2 0
2 2
2 4
2 6
2 8
3 0
3 2
3 4
3 6
MP
G
• Car’s median: approx. 28
• SUV’s median: approx. 22
• Truck’s median: approx. 21
B o x P lo t (S p re a d sh e e t1 1 0 v*3 2 c)
M e d i a n 2 5 % -7 5 % No n -O u tl i e r Ra n g e O u tl i e rs E xtre m e s
Fo rdCa d i l l a c
Hyu n d a iM i tsu b i sh i
Ch e vro le tT o yo ta
Nissa n
b ra n d
1 6
1 8
2 0
2 2
2 4
2 6
2 8
3 0
3 2
3 4
3 6
MP
G
• Not one brand is relatively different from another -- All medians lie in low 20 MPG
• Overall, similar distributions
• However, noticeable difference with Hyundai -- Median: 26
Note: Mitsubishi excluded from analysis because represented by only one car; not fair representation
B o x P lo t (S p re a d sh e e t1 1 0 v*3 2 c)
M e d i a n 2 5 % -7 5 % No n -O u tl i e r Ra n g e O u tl i e rs E xtre m e s
1 7 6 4 02 1 6 2 5
2 5 6 1 02 9 5 9 5
3 3 5 8 03 7 5 6 5
4 1 5 5 04 5 5 3 5
4 9 5 2 05 3 5 0 5
5 7 4 9 0
Co st
1 6
1 8
2 0
2 2
2 4
2 6
2 8
3 0
3 2
3 4
3 6
MP
G
• Price increases as MPG decreases
• Correlation between MPG & Cost = .79 strong, positive correlation
• International car companies have better fuel efficiency compared to American cars
• Medians slightly lower for American cars
• Foreign producers have no outliers in data
• American car companies have been trying to move toward more fuel efficient models, BUT...
• Continue to produce huge cars
• Trucks & pick-ups are part of American image
• The higher the MPG, the lower the cost of the car
• The car with the higher MPG is the best buy, unless large car is necessary
• Smaller car is probably more efficient with gas
• Cheaper, less materials needed to manufacture
