This Ex Post Facto study compared standardized test scores of grade nine students in urban high
schools of the same school district being taught algebra in the classroom using Computer
Assisted Instruction (CAI) to students being taught in the classroom without the use of
computers, Traditional Method Instruction (TMI). Comparison of each group's mean score on
the NPSS, a norm-referenced test, was used to determine if there was a statistically significant
difference in scoring by each group. Additional testing for interaction of gender with the
treatment was done. Four algebra classrooms throughout the district having data on the NPSS
were found to use CAI during the period of 1995 to 1999. The students used PLATO software.
Out of over 8000 students, a total of 64 students were found who received CAI, but only 45 had
NPSS test scores. A group of 45 randomly selected students in the TMI group were paired for
gender and school. Using an analysis of variance (ANOVA) (p = .05), results indicated that the
TMI group in grade nine scored significantly higher (p = .010488). Additionally, the CAI group
compared their grade eight and nine scores. Of the 45 who had NPSS scores in grade nine only
24 had NPSS scores in grade eight. An ANOVA indicated there was no significant difference in
scores from grade eight to grade nine (.p = .0.922628). Testing for interaction of gender and
treatment with this group resulted in no significant change in NPSS scores.