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
y

m x + b

x 1 2 3 4 5 6 y 70 82 102 112 141 152

Solution

To find the equation of the line that best fits the given data using linear regression, we need to compute the slope mm and the y-intercept bb of the line. The equation of the line is:

y=mx+by = mx + b

Here, we are given the following data points:

x:1,2,3,4,5,6x: 1, 2, 3, 4, 5, 6 y:70,82,102,112,141,152y: 70, 82, 102, 112, 141, 152

Step 1: Calculate the Slope mm

The formula for the slope mm in linear regression is:

m=nxiyixiyinxi2(xi)2m = \frac{n\sum{x_i y_i} - \sum{x_i} \sum{y_i}}{n \sum{x_i^2} - (\sum{x_i})^2}

where:

  • nn is the number of data points,
  • xix_i and yiy_i are the values for xx and yy,
  • xi\sum{x_i} is the sum of all xx-values,
  • yi\sum{y_i} is the sum of all yy-values,
  • xiyi\sum{x_i y_i} is the sum of the product of each pair of xx and yy,
  • xi2\sum{x_i^2} is the sum of the squares of all xx-values.

Step 2: Calculate the Y-Intercept bb

Once we have the slope mm, the y-intercept bb is calculated by the formula:

b=yimxinb = \frac{\sum{y_i} - m \sum{x_i}}{n}

Let me calculate the values now.

Step 3: Perform the Calculation

We will first compute all the necessary sums:

  • xi=1+2+3+4+5+6=21\sum{x_i} = 1 + 2 + 3 + 4 + 5 + 6 = 21
  • yi=70+82+102+112+141+152=659\sum{y_i} = 70 + 82 + 102 + 112 + 141 + 152 = 659
  • xi2=12+22+32+42+52+62=1+4+9+16+25+36=91\sum{x_i^2} = 1^2 + 2^2 + 3^2 + 4^2 + 5^2 + 6^2 = 1 + 4 + 9 + 16 + 25 + 36 = 91
  • xiyi=(1×70)+(2×82)+(3×102)+(4×112)+(5×141)+(6×152)=70+164+306+448+705+912=2605\sum{x_i y_i} = (1 \times 70) + (2 \times 82) + (3 \times 102) + (4 \times 112) + (5 \times 141) + (6 \times 152) = 70 + 164 + 306 + 448 + 705 + 912 = 2605

Now, applying these sums to the formulas for mm and bb:

m=6(2605)(21)(659)6(91)(21)2m = \frac{6(2605) - (21)(659)}{6(91) - (21)^2} m=1563013839546441m = \frac{15630 - 13839}{546 - 441} m=1791105=17.06m = \frac{1791}{105} = 17.06

Now, calculate bb:

b=65917.06(21)6b = \frac{659 - 17.06(21)}{6} b=659358.266=300.746=50.12b = \frac{659 - 358.26}{6} = \frac{300.74}{6} = 50.12

Final Equation

The equation of the line that best fits the data is:

y=17.06x+50.12y = 17.06x + 50.12

Would you like more details on how these calculations work, or any other related concepts?

Here are some related questions you might find helpful:

  1. How do you calculate the correlation coefficient to measure the strength of the linear relationship?
  2. What is the significance of the slope and intercept in the context of this problem?
  3. How can you graph the line of best fit using these values?
  4. What is the difference between simple linear regression and multiple linear regression?
  5. How does the least squares method work for finding the line of best fit?

Tip: To interpret the slope, it tells you how much the yy-value changes for every 1-unit increase in xx.

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Algebra
Statistics

Formulas

Slope formula: m = (nΣ(xy) - ΣxΣy) / (nΣ(x^2) - (Σx)^2)
Intercept formula: b = (Σy - mΣx) / n
Equation of a line: y = mx + b

Theorems

Least Squares Method

Suitable Grade Level

Grades 9-12