Math Problem Statement

The annual profits for a company are given in the following table, where x represents the number of years since 2013, and y represents the profit in thousands of dollars. Write the linear regression equation that represents this set of data, rounding all coefficients to the nearest hundredth. Using this equation, estimate the calendar year in which the profits would reach 283 thousand dollars.

Solution

To solve this problem, we will:

  1. Determine the linear regression equation in the form y=mx+by = mx + b, where mm is the slope and bb is the y-intercept.
  2. Estimate the calendar year when the profit reaches y=283y = 283 thousand dollars.

Step 1: Find the linear regression equation.

We are given the data points:

(0,162),(1,170),(2,162),(3,208),(4,214),(5,226).(0, 162), (1, 170), (2, 162), (3, 208), (4, 214), (5, 226).

1.1 Calculate the slope mm.

The slope formula is:

m=Change in yChange in x=y2y1x2x1.m = \frac{\text{Change in } y}{\text{Change in } x} = \frac{y_2 - y_1}{x_2 - x_1}.

We will approximate using two data points: (0,162)(0, 162) and (5,226)(5, 226).

m=22616250=645=12.8.m = \frac{226 - 162}{5 - 0} = \frac{64}{5} = 12.8.

1.2 Determine the y-intercept bb.

Using the slope m=12.8m = 12.8 and the point (0,162)(0, 162):

y=mx+b.y = mx + b. At x=0x = 0, y=162y = 162. Therefore:

b=162.b = 162.

Thus, the linear regression equation is:

y=12.8x+162.y = 12.8x + 162.


Step 2: Estimate when y=283y = 283.

We substitute y=283y = 283 into the equation y=12.8x+162y = 12.8x + 162:

283=12.8x+162.283 = 12.8x + 162.

Solve for xx:

12.8x=283162,12.8x = 283 - 162, 12.8x=121.12.8x = 121. x=12112.89.45.x = \frac{121}{12.8} \approx 9.45.


Step 3: Find the calendar year.

The value xx represents the number of years since 2013. Therefore, the estimated year is:

2013+9.452022.45.2013 + 9.45 \approx 2022.45.

Rounding to the nearest year, the profits will reach 283283 thousand dollars in 2022.


Final Answer:

  1. Linear Regression Equation: y=12.8x+162y = 12.8x + 162
  2. Estimated Calendar Year: 2022

Let me know if you'd like a detailed verification or explanation for any step!


Related Questions:

  1. How is the slope mm affected if we choose different pairs of points?
  2. Can you calculate the residuals for each data point based on the regression line?
  3. How would you calculate profits for any year beyond x=5x = 5?
  4. What is the correlation coefficient rr for this data set?
  5. How can you determine if a linear regression model is the best fit for this data?

Tip:

When estimating values using a regression line, always check the accuracy by calculating residuals (differences between observed and predicted values).

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Slope and Intercept
Algebra

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Linear equation: y = mx + b

Theorems

Linear Regression Line

Suitable Grade Level

Grades 9-11