Math Problem Statement

Use linear regression to find the equation for the linear function that best fits this data. Round both numbers to two decimal places. Write your final answer in a form of an equation x 1 2 3 4 5 6 y 86 108 126 160 181 193

Solution

To find the equation of the linear function that best fits the given data using linear regression, we will calculate the slope (mm) and the y-intercept (bb) of the line in the form y=mx+by = mx + b.

Given data points: x:1,2,3,4,5,6x: 1, 2, 3, 4, 5, 6 y:86,108,126,160,181,193y: 86, 108, 126, 160, 181, 193

Step 1: Calculate the means of xx and yy

xˉ=1+2+3+4+5+66=216=3.5\bar{x} = \frac{1 + 2 + 3 + 4 + 5 + 6}{6} = \frac{21}{6} = 3.5 yˉ=86+108+126+160+181+1936=8546142.33\bar{y} = \frac{86 + 108 + 126 + 160 + 181 + 193}{6} = \frac{854}{6} \approx 142.33

Step 2: Calculate the slope (mm)

The formula for the slope mm is: m=(xixˉ)(yiyˉ)(xixˉ)2m = \frac{\sum{(x_i - \bar{x})(y_i - \bar{y})}}{\sum{(x_i - \bar{x})^2}}

Let's compute the sums needed: (xixˉ)(yiyˉ)=(13.5)(86142.33)+(23.5)(108142.33)++(63.5)(193142.33)\sum{(x_i - \bar{x})(y_i - \bar{y})} = (1-3.5)(86-142.33) + (2-3.5)(108-142.33) + \dots + (6-3.5)(193-142.33) =(2.5)(56.33)+(1.5)(34.33)+(0.5)(16.33)+(0.5)(17.67)+(1.5)(38.67)+(2.5)(50.67)= (-2.5)(-56.33) + (-1.5)(-34.33) + (-0.5)(-16.33) + (0.5)(17.67) + (1.5)(38.67) + (2.5)(50.67) =140.825+51.495+8.165+8.835+58.005+126.675=394.0= 140.825 + 51.495 + 8.165 + 8.835 + 58.005 + 126.675 = 394.0

(xixˉ)2=(13.5)2+(23.5)2++(63.5)2\sum{(x_i - \bar{x})^2} = (1-3.5)^2 + (2-3.5)^2 + \dots + (6-3.5)^2 =(2.5)2+(1.5)2+(0.5)2+(0.5)2+(1.5)2+(2.5)2= (-2.5)^2 + (-1.5)^2 + (-0.5)^2 + (0.5)^2 + (1.5)^2 + (2.5)^2 =6.25+2.25+0.25+0.25+2.25+6.25=17.5= 6.25 + 2.25 + 0.25 + 0.25 + 2.25 + 6.25 = 17.5

m=394.017.522.51m = \frac{394.0}{17.5} \approx 22.51

Step 3: Calculate the y-intercept (bb)

The y-intercept bb is calculated using the formula: b=yˉmxˉb = \bar{y} - m\bar{x} b=142.3322.51×3.5142.3378.78563.54b = 142.33 - 22.51 \times 3.5 \approx 142.33 - 78.785 \approx 63.54

Step 4: Write the final equation

The linear equation that best fits the data is: y=22.51x+63.54y = 22.51x + 63.54

Would you like more details or have any questions?

Here are 5 related questions you might find interesting:

  1. How would the linear regression change if an outlier was added to the data set?
  2. How can you determine the strength of the fit in a linear regression?
  3. What are some real-world applications of linear regression?
  4. How does linear regression differ from multiple regression?
  5. Can linear regression be used to predict values outside the given range of data?

Tip: In linear regression, it's important to check if the relationship between the variables is actually linear, as using a linear model for nonlinear data can lead to inaccurate predictions.

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Statistics

Formulas

Linear regression equation: y = mx + b

Theorems

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Suitable Grade Level

Grades 9-12