Introduction
Correlation and regression analyses were performed to determine the relationship between car retail price and car mileage in Dubai market. Research data was obtained through random sampling. A questionnaire was given to randomly selected customers in the Dubai car market. Ms Excel was used to perform the analyses.
Overview of Data
The car retail prices were presented in form of price ranges. The price ranges were coded as follows: 1 – <$3000, 2 – ($3000 to $6000), 3 – ($6001 to $9000), 4 – ($9001 to $12000), 5 – ($12001 to $15000), 6 – ($15001 to $18000), 7 – ($18001 to $21000), 8 – ($21001 to $23000), 9 – ($23001 to $26000), 10 – ($26001 to $29000) and 11 – ($30000 and above). The following mileages were observed: 0, 50000, 100000, 120000, 140000, 150000 and 200000.
Measures of Central Tendency and Dispersion
Measures of central tendency (mean, median and mode) and measures of dispersion (standard deviation and range) are summarized in table 1.
As shown in table 1, the mean as well as the median and most frequent car retail price ranges is between zero and $3000. The mean car mileage is about 109,285.7143 miles while the median mileage is 125,000 miles. The standard deviation for the car mileage is 66610.09505 while the range (difference between minimum and maximum value) is 200000. It is not meaningful to determine the standard deviation or range for the car retail price ranges.
Correlation and Regression
Correlation analysis produced an R value (correlation coefficient) of about -0.9756. This implies that a very strong negative relationship (correlation) exists between car retail price and mileage.
The R-square value of 0.951887 suggests that the regression model was a perfect fit for the data. In other words, approximately 95.19% of the variations in the car retail prices were accounted for by the car mileage data.
The results of the analysis of variance, P < 0.001 (table 2) mean that the regression model is significant. The regression model can be represented by the following equation: car retail price = 3.078937 – 0.000011 car mileage. The model shows that for every unit increase in mileage, the car retail price range decreases by 0.000011.
Conclusion
In Dubai car market, the car retail price and car mileage are negatively correlated: the car retail price would be high when the car mileage is low but low when the car mileage is high. The relationship can be represented by the regression equation, car retail price = 3.078937 – 0.000011 car mileage.