Math Problem Statement

find the least squares line: (1,16.7) (3,26) (5,33.3) (7,48.3) (9,57) (11,65.8) (13,74.2) (15,83.3)

Solution

To find the least squares line (also known as the line of best fit) for the given set of points, we can use the formulas for the slope mm and the y-intercept bb of the line y=mx+by = mx + b. The formulas are as follows:

m=nxyxynx2(x)2m = \frac{n\sum{xy} - \sum{x}\sum{y}}{n\sum{x^2} - (\sum{x})^2}

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

where:

  • nn is the number of data points,
  • xx and yy are the coordinates of the points,
  • xy\sum{xy} is the sum of the product of each pair of xx and yy,
  • x2\sum{x^2} is the sum of the squares of each xx,
  • x\sum{x} is the sum of all xx values, and
  • y\sum{y} is the sum of all yy values.

Given the points (1,16.7)(1, 16.7), (3,26)(3, 26), (5,33.3)(5, 33.3), (7,48.3)(7, 48.3), (9,57)(9, 57), (11,65.8)(11, 65.8), (13,74.2)(13, 74.2), and (15,83.3)(15, 83.3), let's calculate mm and bb.

I'll perform the calculations step by step.The least squares line that best fits the given data points is:

y=4.842x+11.842y = 4.842x + 11.842

This equation suggests that the slope mm is approximately 4.8424.842 and the y-intercept bb is approximately 11.84211.842.

Would you like further details or have any questions?

Here are some related questions you might find helpful:

  1. How do you interpret the slope and intercept of the least squares line?
  2. What are the properties of the least squares line?
  3. How would you calculate the residuals for this line?
  4. How can you use the least squares line to make predictions?
  5. What is the correlation coefficient, and how is it related to the least squares line?
  6. How does the sum of squared residuals relate to the least squares method?
  7. What is the meaning of a positive vs. a negative slope in a linear regression?
  8. How does the choice of data points affect the least squares line?

Tip: When interpreting the slope of a least squares line, remember that it represents the change in the dependent variable (y) for a one-unit change in the independent variable (x).

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Least Squares Method

Formulas

Formula for slope (m)
Formula for y-intercept (b)

Theorems

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Suitable Grade Level

High School