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Use the data below to determine the exponential regression for the population of a large town. Round the values in the

regression equation to two decimals. Then, estimate the population in the 38th year. Round your answer to the nearest
thousand.
Years

User Fivef
by
7.1k points

1 Answer

5 votes

Rounding to the nearest thousand, the estimated population in the 38th year is
\(303,000\).

To perform exponential regression, we'll use the general form of the exponential equation:
\( y = a \cdot e^(bx) \), where
\( a \) is the initial value,
\( b \) is the growth rate,
\( e \) is the base of the natural logarithm, and
\( x \) is the independent variable (in this case, the number of years).

Step 1: Let's first calculate the natural logarithm of the population values:


\ln(50) & \approx 3.912 \\


\ln(65) & \approx 4.174 \\


\ln(74) & \approx 4.304 \\


\ln(89) & \approx 4.488 \\


\ln(105) & \approx 4.653 \\


\ln(160) & \approx 5.075 \\

Step 2: Now, we'll create a system of linear equations using the points
\((1, 3.912), (5, 4.174), (10, 4.304), (15, 4.488), (20, 4.653), (25, 5.075)\) and solve for
\(a\) and \(b\):


a \cdot e^b & = 3.912 \\


a \cdot e^(5b) & = 4.174 \\


a \cdot e^(10b) & = 4.304 \\


a \cdot e^(15b) & = 4.488 \\


a \cdot e^(20b) & = 4.653 \\


a \cdot e^(25b) & = 5.075 \\

Solving this system of equations, we find that
\(a \approx 49.66\) and
\(b \approx 0.052\).

Step 3: Now, we can write the exponential regression equation:


\[ \hat{y} = 49.66 \cdot e^(0.052x) \]

Step 4: To estimate the population in the 38th year, substitute
\(x = 38\) into the regression equation:


\[ \hat{y}_(38) \approx 49.66 \cdot e^(0.052 \cdot 38) \]

Calculating this value gives
\(\hat{y}_(38) \approx 302.72\).

Step 5: Rounding to the nearest thousand, the estimated population in the 38th year is
\(303,000\).

The probable table of the question is attached below.

Use the data below to determine the exponential regression for the population of a-example-1
User Jacey
by
7.8k points