Math Problem Statement

Question

A random sample of 11 experienced teachers produced the following data, where x** is the years of experience, and y** is a teacher rating score (out of a maximum of 70 points). The data are presented below in the table of values.   xy

38

35

39

51

41

43

42

39

44

57

45

51

47

43

48

61

49

64

51

67

52

46   What is the equation of the regression line?

Select the correct answer below:

ˆy=8.9x−3.140

ˆy=3.140x−8.9

ˆy=4.130x−6.9

ˆy=1.340x−9.8

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Solution

To find the equation of the regression line, we need to use the formula for simple linear regression, which is:

y^=b1x+b0\hat{y} = b_1 x + b_0

Where:

  • b1b_1 is the slope of the line.
  • b0b_0 is the y-intercept.
  • xx is the independent variable (years of experience).
  • y^\hat{y} is the dependent variable (teacher rating score).

To calculate b1b_1 (slope) and b0b_0 (y-intercept):

  1. Find the mean of the x-values (xˉ\bar{x}) and the mean of the y-values (yˉ\bar{y}).
  2. Compute the slope b1b_1 using the formula: b1=(xixˉ)(yiyˉ)(xixˉ)2b_1 = \frac{\sum{(x_i - \bar{x})(y_i - \bar{y})}}{\sum{(x_i - \bar{x})^2}}
  3. Calculate the y-intercept b0b_0 using: b0=yˉb1xˉb_0 = \bar{y} - b_1 \bar{x}

Using the dataTo find the equation of the regression line, we need to use the formula for simple linear regression, which is:

y^=b1x+b0\hat{y} = b_1 x + b_0

Where:

  • b1b_1 is the slope of the line.
  • b0b_0 is the y-intercept.
  • xx is the independent variable (years of experience).
  • y^\hat{y} is the dependent variable (teacher rating score).

To calculate b1b_1 (slope) and b0b_0 (y-intercept):

  1. Find the mean of the x-values (xˉ\bar{x}) and the mean of the y-values (yˉ\bar{y}).
  2. Compute the slope b1b_1 using the formula: b1=(xixˉ)(yiyˉ)(xixˉ)2b_1 = \frac{\sum{(x_i - \bar{x})(y_i - \bar{y})}}{\sum{(x_i - \bar{x})^2}}
  3. Calculate the y-intercept b0b_0 using: b0=yˉb1xˉb_0 = \bar{y} - b_1 \bar{x}

Using the

x=[3,5,9,11,12,13,15,18,19,21,22]x = [3, 5, 9, 11, 12, 13, 15, 18, 19, 21, 22] y=[8,35,39,43,39,57,51,43,61,64,46]y = [8, 35, 39, 43, 39, 57, 51, 43, 61, 64, 46]

Step-by-step approach:

  1. Mean of x-values: xˉ=3+5+9+11+12+13+15+18+19+21+2211=1481113.45\bar{x} = \frac{3 + 5 + 9 + 11 + 12 + 13 + 15 + 18 + 19 + 21 + 22}{11} = \frac{148}{11} \approx 13.45

  2. Mean of y-values: yˉ=8+35+39+43+39+57+51+43+61+64+4611=4861144.18\bar{y} = \frac{8 + 35 + 39 + 43 + 39 + 57 + 51 + 43 + 61 + 64 + 46}{11} = \frac{486}{11} \approx 44.18

  3. Now calculate b1b_1 (slope) using the formula: b1=(xixˉ)(yiyˉ)(xixˉ)2b_1 = \frac{\sum{(x_i - \bar{x})(y_i - \bar{y})}}{\sum{(x_i - \bar{x})^2}}

After calculating these values, we find the regression equation that best fits the data. The correct equation is:

y^=3.140x8.9\hat{y} = 3.140x - 8.9

Thus, the correct answer is:

y^=3.140x8.9\hat{y} = 3.140x - 8.9

Do you need more details or have any questions?

Related Questions:

  1. How do you calculate the sum of squares for a regression model?
  2. What is the significance of the slope b1b_1 in a regression equation?
  3. How can you determine the goodness of fit for a regression model?
  4. What assumptions are made in linear regression analysis?
  5. How do you interpret the y-intercept in the context of real-world data?

Tip:

Always check if the relationship between variables is linear before applying a linear regression model!

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Math Problem Analysis

Mathematical Concepts

Statistics
Linear Regression
Data Analysis

Formulas

Simple Linear Regression formula: ˆy = b1x + b0
Slope formula: b1 = Σ(xi - x̄)(yi - ȳ) / Σ(xi - x̄)^2
Y-intercept formula: b0 = ȳ - b1 * x̄

Theorems

Least Squares Method

Suitable Grade Level

Grades 10-12