Question

 

Analyze the data set (e.g. mean, standard deviation, scatterplot, histogram, bar chart, etc.)and discuss important findings. Suggest courses of action related to the given situation.

Variable Names:
1. VOL: Cubic feet of cab space
2. HP: Engine horsepower
3. MPG: Average miles per gallon
4. SP: Top speed (mph)
5. WT: Vehicle weight (100 lb)
MAKE / MODEL	VOL	HP	MPG	SP	WT
GM/GeoMetroXF1	89	49	65.4	96	17.5
GM/GeoMetro	92	55	56	97	20
GM/GeoMetroLSI	92	55	55.9	97	20
SuzukiSwift	92	70	49	105	20
DaihatsuCharade	92	53	46.5	96	20
GM/GeoSprintTurbo	89	70	46.2	105	20
GM/GeoSprint	92	55	45.4	97	20
HondaCivicCRXHF	50	62	59.2	98	22.5
HondaCivicCRXHF	50	62	53.3	98	22.5
DaihatsuCharade	94	80	43.4	107	22.5
SubaruJusty	89	73	41.1	103	22.5
HondaCivicCRX	50	92	40.9	113	22.5
HondaCivic	99	92	40.9	113	22.5
SubaruJusty	89	73	40.4	103	22.5
SubaruJusty	89	66	39.6	100	22.5
SubaruJusty4wd	89	73	39.3	103	22.5
ToyotaTercel	91	78	38.9	106	22.5
HondaCivicCRX	50	92	38.8	113	22.5
ToyotaTercel	91	78	38.2	106	22.5
FordEscort	103	90	42.2	109	25
HondaCivic	99	92	40.9	110	25
PontiacLeMans	107	74	40.7	101	25
IsuzuStylus	101	95	40	111	25
DodgeColt	96	81	39.3	105	25
GM/GeoStorm	89	95	38.8	111	25
HondaCivicCRX	50	92	38.4	110	25
HondaCivicWagon	117	92	38.4	110	25
HondaCivic	99	92	38.4	110	25
Subaru Loyale	102	90	29.5	109	25
VolksJettaDiesel	104	52	46.9	90	27.5
Mazda323Protege	107	103	36.3	112	27.5
FordEscortWagon	114	84	36.1	103	27.5
FordEscort	101	84	36.1	103	27.5
GM/GeoPrism	97	102	35.4	111	27.5
ToyotaCorolla	113	102	35.3	111	27.5
EagleSummit	101	81	35.1	102	27.5
NissanCentraCoupe	98	90	35.1	106	27.5
NissanCentraWagon	88	90	35	106	27.5
ToyotaCelica	86	102	33.2	109	30
ToyotaCelica	86	102	32.9	109	30
ToyotaCorolla	92	130	32.3	120	30
ChevroletCorsica	113	95	32.2	106	30
ChevroletBeretta	106	95	32.2	106	30
ToyotaCorolla	92	102	32.2	109	30
PontiacSunbirdConv	88	95	32.2	106	30
DodgeShadow	102	93	31.5	105	30
DodgeDaytona	99	100	31.5	108	30
EagleSpirit	111	100	31.4	108	30
FordTempo	103	98	31.4	107	30
ToyotaCelica	86	130	31.2	120	30
ToyotaCamry	101	115	33.7	109	35
ToyotaCamry	101	115	32.6	109	35
ToyotaCamry	101	115	31.3	109	35
ToyotaCamryWagon	124	115	31.3	109	35
OldsCutlassSup	113	180	30.4	133	35
OldsCutlassSup	113	160	28.9	125	35
Saab9000	124	130	28	115	35
FordMustang	92	96	28	102	35
ToyotaCamry	101	115	28	109	35
ChryslerLebaronConv	94	100	28	104	35
DodgeDynasty	115	100	28	105	35
Volvo740	111	145	27.7	120	35
FordThunderbird	116	120	25.6	107	40
ChevroletCaprice	131	140	25.3	114	40
LincolnContinental	123	140	23.9	114	40
ChryslerNewYorker	121	150	23.6	117	40
BuickReatta	50	165	23.6	122	40
OldsTrof/Toronado	114	165	23.6	122	40
Oldsmobile98	127	165	23.6	122	40
PontiacBonneville	123	165	23.6	122	40
LexusLS400	112	245	23.5	148	40
Nissan300ZX	50	280	23.4	160	40
Volvo760Wagon	135	162	23.4	121	40
Audi200QuatroWag	132	162	23.1	121	40
BuickElectraWagon	160	140	22.9	110	45
CadillacBrougham	129	140	22.9	110	45
CadillacBrougham	129	175	19.5	121	45
Mercedes500SL	50	322	18.1	165	45
Mercedes560SEL	115	238	17.2	140	45
JaguarXJSConvert	50	263	17	147	45
BMW750IL	119	295	16.7	157	45
Rolls-RoyceVarious	107	236	13.2	130	55

Answer 1

"This approach is the most suitable course of action that can be undertaken."

Use Excel for best results and let me know in case you are stuck somewhere.

To obtain meaningful inference from the dataset, I have isolated the Car Company and Car Type in different columns. All the statistics will be calculated for the 28 different Car Companies and comparisons would be then drawn from the overall results.

Firstly find the database in the following pictures:

MEAN (AVERAGE)

Now we calculate the mean for the different "Car Companies"

To calculate the same we have simply picked a car maker, eg:- Buick and we are finding the average VOL. We use the formula (50+160)/2=105.

Similiarly we are calculating the means of all the variables with reference to the car company.

Inferences Drawn:

• Rolls-Royce gives the lowest mean of MPG i.e. 13.20 Miles Per Gallon while GM gives the highest mean i.e. 49.01 Miles Per Gallon . The cars gives an average MPG of 33.78 Miles Per Gallon. So users looking for high mileage in their cars should not buy Rolls-Royce cars.
• Cubic feet of cab space is lowest on an average in Jaguar, only 50, while it is the highest in Audi, a cool 132. On an average it is 98.80 in all cars.
• Mean horsepower is lowest in Volks, a dismal 52 while it is the highest in BMW - 295. The average horespower in all vehicles is 117.13.
• Suzuki cars are the lightest on an average while Rolls-Royce are the heaviest. (Both in weight and your pocket!)
• Volks vehicles have the lowest mean top speed of 90 mph while BMW vehicles have the highest mean top speed of 157 mph.

STANDARD DEVIATION:

It is a measure of how far apart the results vary from the mean value. For the different car companies it is calculated using the formula:

n= number of cars

Inferences Drawn:

• Overall, the vehicle weights show the minimum standard deviation showing that all cars are closest in respect of weight than any of the other variables.
• The most variability is shown in Engine horsepower. All the different car companies differ mostly in their engine horsepower.
• For a particular car company, the variability of all different parameters, between the different car models are shown in the table. In this case for individual car companies, the more variability there is, the better is the scope of the models produced i.e. the more variety of models produced suiting different sets of customers.

BAR GRAPH

SCATTERPLOT

• Horsepower has the most scattered values while the least scattered values are shown by weight.