The following contains a brief description of a hypothetical research study in psychology. Read the description and respond to the questions that are posed.
interested in the acquisition of foreign language skills performed an experiment
to assess the effectiveness of new computer software designed to teach German
vocabulary and grammar to high school students. From the total of 74 students
signed up to take the Freshman German course at Trafalger High School, thirty
were randomly selected for inclusion in the research study. The thirty students
were randomly assigned to one of two classes: Class C and Class E. The fifteen
students assigned to Class E were taught by the Head of the Foreign Language
Department, Ms. Eccle, and this class met Monday through Friday from 9:00 -
9:50 a.m. In addition, Ms. Eccle's class was required to meet in the language
lab from 3:00 - 3:50 on Tuesdays and Thursdays to work with the computer software,
the effectiveness of which was the focus of the study. The fifteen students
assigned to Class C were taught by another German teacher, Ms. Corbin, and this
class met Monday through Friday from 1:00 - 1:50 p.m. No additional instruction
was given to Ms. Corbin's class, and the students were never exposed to the
At the end of the semester the experimenter administered a standard test of German vocabulary and grammar to each class. The average percentage score for Class E (Ms. Eccle's class) was 84%, with a high of 99% and a low of 72%. The average for Class C (Ms. Corbin's class) was 71%, with a high of 85% and a low of 52%. This result led the investigator to conclude that the computer software was extremely effective and reported this to the software manufacturer. The manufacturer decided to immediately mount an advertising campaign directed at public schools, using the results of this research to tout the effectiveness of its software.