In investigating which of two presentations of subject matter to use in a computerprogrammed course, an experimenter randomly chose two groups of 18 students each, and assigned one group to receive presentation I and the second to receive presentation II. A short quiz on the presentation was given to each group and their grades recorded. Do the following data indicate that the difference in the mean quiz scores (hence difference in effectiveness of presentation) exists for the two methods? Find the approximate p-value, interpret your results and state your assumptions.(α = 0.05).
Presentation I: mean=81.7, std dev=23.2
Presentation II: mean=77.2, std dev= 19.8