CAR MODELS
SOLD IN US 2003-2004
STINE & FOSTER 4 - 53
CARS PROBLEM
Another columns in this data file cars gives the rating
highway gasoline mileage and city gasoline mileage
(in miles per gallon) for 233 car sold in the United
States during 2003 and 2004.
SUMMARY STATISTICS
All Observations
City
Highway
Mean Median Var
StDev CV IQR Skewness
19.24
19 90.93
9.54
0.5
5
-7.65
25.68
26 102.43 10.12 0.39
7
-7.7
Exclude Missing Observation
City
Highway
Mean Median Var
StDev CV IQR Skewness
19.75
19 30.53
5.53 0.28
5
2.74
26.22
26 35.30
5.94 0.23
7
1.57
A)
PRODUCE A HISTOGRAM OF THESE DATA. DESCRIBE AND
INTERPRET THE HISTOGRAM.
B)
COMPARE THE HISTOGRAM TO THE BOX PLOT. WHAT DOES THE
HISTOGRAM TELL YOU THAT THE BOX PLOT DOES NOT, AND
VICE VERSA?
MPG CITY
MPG HIGHWAY
C)
FIND THE MEAN AND STANDARD DEVIATION OF THE RATED
MILEAGES. HOW ARE THESE RELATED TO THE HISTOGRAM, IF AT
ALL?
All Observations
City
Highway
Mean Median Var
StDev CV IQR Skewness
19.24
19 90.93
9.54
0.5
5
-7.65
25.68
26 102.43 10.12 0.39
7
-7.7
Exclude Missing Observation
City
Highway
Mean Median Var
StDev CV IQR Skewness
19.75
19 30.53
5.53 0.28
5
2.74
26.22
26 35.30
5.94 0.23
7
1.57
D)
FIND THE COEFFICIENT OF VARIATION AND BRIEFLY INTERPRET
ITS VALUE.
All Observations
City
Highway
Mean Median Var
StDev CV IQR Skewness
19.24
19 90.93
9.54
0.5
5
-7.65
25.68
26 102.43 10.12 0.39
7
-7.7
Exclude Missing Observation
City
Highway
Mean Median Var
StDev CV IQR Skewness
19.75
19 30.53
5.53 0.28
5
2.74
26.22
26 35.30
5.94 0.23
7
1.57
E)
IDENTIFY ANY UNUSUAL VALUES (OUTLIERS). DO YOU THINK
THAT THESE ARE CODING ERRORS?
A)
PRODUCE A HISTOGRAM OF THESE DATA. DESCRIBE AND
INTERPRET THE HISTOGRAM.
B)
COMPARE THE HISTOGRAM TO THE BOX PLOT. WHAT DOES THE
HISTOGRAM TELL YOU THAT THE BOX PLOT DOES NOT, AND
VICE VERSA?
MPG CITY
MPG HIGHWAY
F)
HOW DOES A CAR THAT GETS 20 MILES PER GALLON STACK UP
AGAINST THESE MODELS? IS IT TYPICAL OR DOES IT GET
RELATIVELY LOW MILE OR HIGH MILEAGE?