With the increasing availability of computers, most students now type their class papers using…

With the increasing availability of computers, most students now type their class papers using word processors rather than typewriters. Because it is so much easier to edit and change text with word processors, we might expect word-processed papers to be better than those simply typed. To test this hypothesis, imagine that we instructed 30 students to write a 1O-page term paper. We randomly assigned 15 students to type their papers on a typewriter and the other 15 students to type their papers on a word processor. (Let's assume all of the students were at least mediocre typists with some experience on a word processor.) After receiving the students' papers, we then retyped all of the papers to be uniform in appearance (to eliminate the confound that would occur because typed and word-processed papers look different). Then, a professor graded each paper on a 10-point scale. The grades were as follows:

a. State the null and experimental hypotheses.

b. Conduct a t-test to determine whether the quality of papers written using a word processor was higher than that of papers typed on a typewriter.