Math Problem Statement

The table below shows the median weekly earnings of a certain population of workers. If this trend​ continues, predict the median weekly earnings in 201616. For this​ exercise, find a linear and a quadratic regression equation and use both to predict the earnings in 201616. Let x be the number of years since the year 2000 and y be the weekly earnings in dollars. Year 2002 2004 2006 2008 2010

Weekly Earnings ​(in dollars) 570570 580580 613613 625625 614614 Question content area bottom Part 1 create A linear regression equation y=?

Solution

Let's solve the problem step by step, beginning with the linear regression equation.

Step 1: Set up the data points.

Since we are told to let xx be the number of years since 2000 and yy be the weekly earnings, we will convert the year values into xx-values:

  • 2002 → x=2x = 2
  • 2004 → x=4x = 4
  • 2006 → x=6x = 6
  • 2008 → x=8x = 8
  • 2010 → x=10x = 10

Thus, the table looks like this:

xx (years since 2000)yy (weekly earnings in dollars)
2570
4580
6613
8625
10614

Step 2: Use the formula for linear regression.

The general form of the linear regression equation is:

y=mx+by = mx + b

Where:

  • mm is the slope,
  • bb is the y-intercept.

Formula for mm (slope):

m=nxy(x)(y)nx2(x)2m = \frac{n \sum{xy} - (\sum{x})(\sum{y})}{n \sum{x^2} - (\sum{x})^2}

Formula for bb (y-intercept):

b=ymxnb = \frac{\sum{y} - m \sum{x}}{n}

Where nn is the number of data points. Let's calculate each term.

Step 3: Calculate the necessary sums.

We need to compute:

  • x\sum{x}
  • y\sum{y}
  • xy\sum{xy}
  • x2\sum{x^2}

Let's calculate these values and then solve for mm and bb.

I'll do the computations now.The linear regression equation is:

y=6.65x+560.5y = 6.65x + 560.5

This represents the trend of median weekly earnings based on the number of years since 2000.

Would you like to proceed with predicting the earnings for 2016 using this equation, or should I first provide the quadratic regression? Let me know!

Here are some related questions for further exploration:

  1. How do we compute the slope in linear regression?
  2. Why is the y-intercept important in regression models?
  3. What are the limitations of linear regression for long-term predictions?
  4. How would the model change if outliers existed in the data?
  5. What real-world factors could cause deviations from this model?

Tip: In a linear regression, always check the residuals to see how well the model fits the data.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Linear Regression
Quadratic Regression
Statistics

Formulas

Linear regression equation: y = mx + b
Slope formula: m = (n∑xy - (∑x)(∑y)) / (n∑x² - (∑x)²)
Y-intercept formula: b = (∑y - m∑x) / n
Quadratic regression: y = ax² + bx + c

Theorems

Least Squares Method

Suitable Grade Level

College Level