Reflection

Category Possible Grade
Temporal Progression 3
Important Aspects of the Experience 3
Connection to Academic Theory 3
Relating to Other Contexts / Draw Connections 6
Personal Thoughts and Feelings 6
Cause-and-Effect Relationships 6
Other Possible Responses 6
Planning and Future Practices 6

Linear regression

The theoretical regression model:

\[ \underbrace{y_i}_{\text{Dependent Variable}} = \underbrace{\beta_0}_{\text{Intercept}} + \underbrace{\beta_1x_{i1} + \beta_2x_{i2} + \cdots + \beta_jx_{ij}}_{\text{Independent Variables}} + \underbrace{\epsilon_i}_{\text{Random Error}} \]

An estimated regression equation:

\[ \hat{y_i} = \hat{\beta_0} + \hat{\beta_1}x_{i1} + \hat{\beta_2}x_{i2} + \cdots + \hat{\beta_j}x_{ij} \]

The loss function minimized with the OLS procedure:

\[ \sum e_i^2 = \sum (y_i - \hat{y_i})^2 = \sum (y_i - \hat{\beta_0} - \hat{\beta_1}x_{i1} - \hat{\beta_2}x_{i2} - \cdots - \hat{\beta_j}x_{ij})^2 \]

Trend surface

General form:

\[ y_i = f(lat_i,long_i) + \epsilon_i \]

First degree:

\[ y_i = \beta_0 + \beta_1lat_i +\beta_2long_i + \epsilon_i \]

Second degree:

\[ y_i = \beta_0 + \beta_1lat_i^2 +\beta_2lat_i + \\ \beta_3lat_i \cdot long_i +\beta_4long_i + \beta_5long_i^2 + \epsilon_i \]

Spatially-varying Coefficients

Expansion Method:

Use the trend surface function in place of a constant coefficient:

\[ y_i = f_{(lat_i, long_i)}^1 + f_{(lat_i, long_i)}^2 x_{i1} + \epsilon_i \]

\[ \begin{array}{l} f_{(lat_i, long_i)}^1 = \beta_{01} +\beta_{02}lat_i + \beta_{03}long_i\\ f_{(lat_i, long_i)}^2 = \beta_{11} +\beta_{12}lat_i + \beta_{13}long_i \end{array} \]

Geographically Weighted Regression:

Instead of fitting a regression model to all the observations, it fits to a subset of them each time based on the bandwidth defined.

It is like a spatial moving average; instead of calculating an average, we are fitting a regression model to each window.

Spatial error model

\[ y_i = \beta_0 + \beta_1x_{i1} + \beta_2x_{i2} + \cdots + \beta_jx_{ij} + \underbrace{\epsilon_i}_{\text{Random Error}} \]

The error term is no longer independent of each other but follows an autoregressive form:

\[ \epsilon_i = \lambda \sum_k w_{ik}\epsilon_k + u_i \]

Noting that the \(u_i\) is the pure random component now.

Capstone activity expectation

For lab activity submission, you need to at least conduct descriptive statistics.

Load the data and use the summary method or provide some descriptive plots like histograms.

Activities for today

  • We will work on the following chapter from the textbook:
    • Chapter 28: Activity 13: Area Data V
    • Chapter 30: Activity 14: Area Data VI
  • The hard deadline is Friday, March 14.