An educational psychologist has developed a new textbook based on programmed instruction techniques and wishes to know if it is superior to the conventional kind of textbook. He therefore obtains participants who have had no prior exposure to the material and forms two groups: an experimental group, which learns via the programmed text, and a control group, which learns via the old-fashioned textbook. The psychologist is afraid, however, that differences among participants in overall intelligence will lead to large error terms. Therefore, he matches his participants on intelligence and forms 10 pairs such that each pair is made up of two people roughly equal in intelligence test scores. After both groups have learned the material, the psychologist measures the amount of learning by means of a 10-item quiz. The results are as follows:

Test the results for statistical significance at the .05 level. What should the psychologist decide about his or her new programmed text?

Experimental group||Control group Pair (programmed text) (standard text) 3 5 4 5 3 4 15 6. 10 10 6. 3. 3. 3.