Math Problem Statement
The following table shows the value of a car over time that was purchased for 18200 dollars, where x is years and y is the value of the car in dollars.
Write an exponential regression equation for this set of data, rounding all coefficients to the nearest hundredth.
Years (x) | Value $ (y)
0 | 18200
1 | 14824
2 | 13651
3 | 11593
4 | 10590
Use y = a(b)^x as your regression equation.
Solution
To solve this problem, we need to compute an exponential regression model in the form:
Steps:
-
Determine :
- represents the initial value of when . From the table, .
-
Determine :
- is the growth (or decay) factor and can be calculated as: Here, is the initial value (18200), and is the value at . We will use several values to calculate .
-
Calculate the correlation coefficient :
- This measures how well the exponential model fits the data.
Let me calculate these values for you.Here are the results for the exponential regression:
- (initial value when ).
- (decay factor, rounded to the nearest hundredth).
- (correlation coefficient, indicating a strong negative relationship).
Regression equation:
Let me know if you need detailed explanations for any step or additional analysis!
Related Questions:
- How does the correlation coefficient affect the interpretation of the model's fit?
- Can you calculate the expected value of the car after 5 years using the regression equation?
- How would the regression change if the decay factor were larger than 1?
- Why is exponential regression appropriate for this data instead of linear regression?
- How can we verify the model's accuracy with residuals?
Tip:
In exponential models, the decay factor gives a direct measure of the rate of decrease (or increase) per unit of .
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Math Problem Analysis
Mathematical Concepts
Algebra
Exponential Decay
Regression Analysis
Formulas
y = a(b)^x
b = (y_n / y_0)^(1/n)
Correlation coefficient (r)
Theorems
-
Suitable Grade Level
Grades 9-12