Auniversity was interested in examining the overall effectiveness of its online statistics course, along with the effectiveness of particular aspects of the course. first, the university wanted to see whether the online course was better than a standard course. second, the university wanted to know whether students learned best using excel, using minitab, or using no statistical package at all. the university randomly selected a group of 30 students and administered one of the different variants of the course (i. e., traditional or online, coupled with one of the software options) to each student. the success of each variant was measured by the students' average improvement between a pre-test and a post-test. a) is this an experiment or an observational study? state what essential characteristics distinguish a true experiment from an observational study. b) which of the following is the explanatory variable(s)? 1) the student's mean pre-test and post-test average scores 2) whether the course was online or traditional 3)whether the course was online or traditional and the statistical software used c) which of the following represents the response variable? 1) the student's mean post-test score. 2) the difference between the students' mean pre-test and post-test scores 3) an evaluation of course quality provided by an independent rater d) how many treatment groups are there in this study? e) if we would like the treatments to be balanced in terms of the number of subjects how many students should we assign to each treatment? should you use table a at the end of the book for randomly selecting subjects or is there a better way? g) after the students complained being assigned to a software that they did not know the university allowed the 30 randomly selected students to select both the type of the course and the type of software themselves. 1) is this an observational study or an experiment? 2) do you think there are lurking variables in the design put forth in g) if so state two of them. f) which study design do you think will give the university a clearer understanding of the factors that affect course effectiveness? the original one or the one described in g)? explain briefly