Assignment 5, Ed31E, Spring 2004: Latent class analysis

Consider the LSAY math attitude items that you worked with in Assignment 2,

!enj7-10 = "I ENJOY MATH"

!good7-10="I AM GOOD AT MATH"

!und7-10= "USUALLY UNDERSTAND MATH"

!useboy7-10 = "MATH MORE USEFUL FOR BOYS"

!nerv7-10 = "MATH MAKES ME NERVOUS"

!wor7-10= "WORRY ABOUT MATH TEST GRADES"

!scar7-10 = "SCARED WHEN I OPEN MATH BOOK"

!use7-10 = "MATH USEFUL IN EVERYDAY PROBLEMS"

!logic7-10= "MATH HELPS LOGICAL THINKING"

!boybet7-10 = "BOYS BETTER AT MATH THAN GIRLS"

!job7-10 ="NEED MATH FOR A GOOD JOB"

!often7-10 = "WILL USE MATH OFTEN AS AN ADULT"

where each item is measured on a 5-point Likert scale: 1-Strongly Agree, 2-Agree, 3-Not sure, 4-Disagree, 5-Strongly Disagree.

Do a latent class (latent profile) analysis of these items or a subset of them. Feel free to dichotomize the items or analyze them in their original quasi-continuous form. Interpret the classes of students that you find and relate them to background variables. Make a graph of how a key continuous background variable influences the class probabilities. Compare your latent class solution to a factor analysis solution by showing the class membership superimposed on a plot of the estimated factor scores similar to what was done on page 15 of the course handout and on pages 8-9 in the Muthen (2001) paper #86, “Latent Variable Mixture Modeling” (this paper is available on the course web site).