Math Problem Statement

Some types of algae have the potential to cause damage to river ecosystems. The accompanying data on y = algae colony density and x = rock surface area for nine rivers are a subset of data that come from a study.

x 51 55 49 79 43 37 69 45 48

y 154 48 24 35 36 171 11 185 27

What is the value of

se

for this data set? (Round your answer to five decimal places.)

Solution

To calculate the value of ses_e, which is the standard error of the estimate, we first need to compute the regression equation (i.e., the line of best fit) for the data. The standard error ses_e is given by:

se=(yiy^i)2n2s_e = \sqrt{\frac{ \sum (y_i - \hat{y}_i)^2 }{n-2}}

Where:

  • yiy_i are the observed values,
  • y^i\hat{y}_i are the predicted values from the regression line,
  • nn is the number of data points.

Steps:

  1. Calculate the regression line equation y=a+bxy = a + bx, where bb is the slope and aa is the intercept.
  2. Use the regression line to compute the predicted values y^i\hat{y}_i.
  3. Calculate the residuals yiy^iy_i - \hat{y}_i for each data point.
  4. Compute the sum of squared residuals (yiy^i)2\sum (y_i - \hat{y}_i)^2.
  5. Finally, compute ses_e using the formula above.

I'll calculate that for you.The standard error of the estimate (ses_e) for the given data set is approximately 65.20796 (rounded to five decimal places).

Would you like further details or have any questions about the calculation?

Here are five related questions to expand your understanding:

  1. How is the slope of the regression line calculated in linear regression?
  2. What does the residual value represent in regression analysis?
  3. Why is n2n - 2 used in the denominator when calculating the standard error of the estimate?
  4. How can you interpret the standard error of the estimate in terms of model fit?
  5. What is the relationship between the correlation coefficient and the goodness of fit?

Tip: The smaller the standard error of the estimate, the better the regression line 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
Standard Error of Estimate
Residuals

Formulas

y = a + bx (Regression equation)
s_e = sqrt(Σ(y_i - ŷ_i)^2 / (n - 2)) (Standard error of estimate)

Theorems

Least Squares Method

Suitable Grade Level

College Level (Statistics/Regression Analysis)