Murtaza Haider firstname.lastname@example.org Tel: 416.979.5000, ext. 2480
Outline • TransCAD’s use for
– Basic tabulations – Statistical analysis – Trip generation models
Tabulations and Statistics • Goal: understand TransCAD’s statistical analysis tools and how you can use them to:
– Generate summary statistics – Perform tabulations and cross-tabulations– Determine correlations between variables – Create, estimate and evaluate linear regression and binary logit models – Calculate spatial autocorrelation
Basics: Statistics • Definition: A branch of mathematics dealing with the collection, analysis, interpretation and presentation of masses of numerical data. In TransCAD, a range of statistical methods are available.
Basics: Tabulation •Definition: A classification of records or features in a layer based on the values for either one or two data fields.
Example: One-Way Tabulation
Example: Two-Way Tabulations
Quick Start: Calculating Summary Statistics • Choose File-Close All, then choose File-Open or click on the toolbar. • Open the DBASE file CUSTOMER.DBF in the TCW\TUTORIAL directory. TransCAD opens a customer salesdatabase. • Choose Dataview-Statistics. TransCAD calculates the summary statistics for the dataview.
Getting Ready for a One-Way Tabulation • Choose File-Close All, then choose File-Open or click on the toolbar. • Open the DBASE file BUS_SURV.DBF in the TCW\EXERCISE directory. TransCAD displays a survey taken from transit riders. • Choose Statistics-Tabulations. TransCAD displays theTabulations dialog box. • Choose AGE in the Field 1 drop-down list.
Performing a One-Way Tabulation • All the other settings are correct. Click OK. • Enter MYTAB as the output filename and click OK. TransCAD creates a tabulation on the AGE field and displays a matrix containing the age distribution. • Make the BUS_SURV dataview the active window. • Choose Statistics-Tabulations again.
Performing aTwo-Way Tabulation • For HH_SIZE from the Field 1 drop-down list and AUTOS from the Field 2 drop-down list. • Choose List of Values from both Methods dropdown lists, and 5 from both # Classes drop-down lists. • Enter MYTAB2 as the output filename and click OK. TransCAD produces a two-way tabulation of AUTOS and HH_SIZE.
In Depth: Tabulations • Choose Statistics-Tabulations to display theTabulations dialog box:
Basics: Correlation • Definition: A calculated statistic that determines the interdependence between mathematical variables. The calculated correlation can range from 1 (perfectly positively correlated) through 0 (no correlation) to -1 (perfectly negatively correlated)
GettingReady to Calculate Correlations • Choose File-Close All, then choose File-Open or click on the toolbar. • Open the DBASE file BUS_SURV.DBF in TCW\EXERCISE. TransCAD displays a survey taken from transit riders. • Choose Statistics-Correlations to display the Correlations dialog box.
Calculating Correlations • Choose AGE, AUTOS, HHINC1000S and EDUCATION from the Fields drop-down list (using the Ctrlkey) and click OK. • Enter MYCORREL as the filename and click OK. TransCAD calculates the correlations among the selected variables and puts the results in a matrix. TransCAD also launches Notepad to display a report file. Close Notepad after reading the report.
Exercise #1 • Open any table that has two or more numerical fields and perform both one- and two-way tabulations on the data fields.Experiment with changing the methods and the number of classes to see the effects on the ranges.
Exercise #2 • Using the same table used in Exercise #1, calculate the correlations of all the fields in the table. Analyze the results and see which fields are positively or negatively correlated with each other.
Statistical Modeling • TransCAD provides various tools for statistical...