Many studies have examined the association between cholesterol levels and coffee consumption. Some studies have muicateu that many coffee bean components have the effect of elevating blood cholesterol levels. A research student has developeu a hew type of paper coffee filter that has the potential effect of reducing the presence of some of these cholesterol increasing coffee bean components An experiment is proposed to study the new filter's effect on cholesterol level over a twelve-week period. 240 nonsmokers who each drank exactly four cups of coffee per day were identified. dra or the 240 participants would then be assigned to one of two groups. The first group, the experimental group, will arink coffee that is only prepared with the new filters, while the second group, the control group, will only drink coffe prepared with the standard filter. The cholesterol level of cach participant will be measure at the beginning and the end of the twelve week study. (a) Describe an appropriate method of assigning the 240 participants (subjects) to the two groups so that each group will have an equal number of people. ) Within this study, the researcher chose to include a group who only drank coffee prepared with standard filters. Why is it important to include a control group in this study even though cholesterol levels will be measure at the beginning and end of the twelve-week period? (1. Describes the need for a Control group. 2. Explains how the Control group allows researchers to attribute change in cholesterol level to the new filter by giving an EXAMPLE of what could cause the change.) Why would the researcher choose to use only nonsmokers in this study? (ldentify what type of variables this is, AND comment in the response variable ") that it is necessary To Reduce_V Another researcher conducting the same experiment choose his participants by putting an ad in the newspaper and asked people to call the provided 1-800 phone number if they wanted to be in the study. He placed the first 120 whe called into the "new filter" group and conducted the experiment. What is the potential problem with this design?