Each day I am getting better in math A "subliminal" message is below our threshold of awareness but may nonetheless influence us. Can subliminal messages help students learn math? A group of students who had failed the mathematics part of the City University of New York Skills Assessment Test agreed to participate in a study to find out. All received a daily subliminal message, flashed on a screen too rapidly to be consciously read. The treatment group of students (assigned at random) was exposed to "Each day I am getting better in math." The control group of students was exposed to a neutral message, "People are walking on the street." All students participated in a summer program designed to improve their math skills, and all took the assessment test again at the end of the program. The following table gives data on the subjects' scores before and after the program.
a. Explain why a two-sample t-test and not a paired t-test is the appropriate inference procedure in this setting.
b. The following boxplots display the differences in pretest and post-test scores for the students in the control (C) and treatment (T) groups. Write a few sentences comparing the performance of these two groups.
c. Do the data provide convincing evidence at the significance level that subliminal messages help students like the ones in this study learn math, on average?
d. Can we generalize these results to the population of all students who failed the mathematics part of the City University of New York Skills Assessment Test? Why or why not?
