Problem 1. The Internet is growing rapidly with an increasing number of regular users. However, among people older than 50, Internet use is still relatively low. To learn more about this issue, a sample of 250 men and women older than 50 who had used the Internet at least once were selected. The number of hours used in the past month was recoded for each. It is found that their sample mean is equal to 5.5 hours. Answer the following questions based on this study. Be as specific as possible. 1. Describe the experimental unit. 2. Describe the population. 3. Describe the variable of interest. 4. Is the variable of interest a quantitative or a qualitative? 5. Is the value 5.5 represents a parameter or a statistic? Problem 2. A medical researcher is interested in testing a new medication for poison ivy. He decides to conduct a clinical trial on 250 volunteers who are allergic to poison ivy. He purposefully rubs poison ivy on their calf, then after the rash appears, he randomly chooses half of the volunteers and gives them calamine lotion, and the other half the new medication. For each volunteer, he measures the amount of time (in minutes) until the rash disappears completely. Identify the following in terms of the above study. Be as specific as possible: 1. The population 2. Experimental Unit 3. Variables – identify which are response(s), and which are explanatory and classify each as quantitative or categorical. 4. Sample 5. Is this study experimental or observational? Justify. 6. Name at least one aspect of the design that you think may be problematic. Suggest an improvement. Problem 3. In a greenhouse study, we are interested in the effects of water and fertilizer nutrients on seedling biomass. Each seedling can have low, medium, or high level of water and low, medium, or high level of nutrients. Suppose we sample 5 seedlings in each combination of water and nutrient level. 1. What are the factors and the levels in this example? 2. Describe what a treatment is in this example? How many treatments are there? 3. Are the factors crossed or nested? 4. What is the response variable? How many observations are there? Problem 4. Our iPhones, Ourselves: Cellphone Separation Anxiety Is Real, Study Finds Yes, your iPhone may be exposing you to more radiation than anyone would like to think about. But is it also priming you for separation anxiety? A new study out of the University of Missouri says yes, yes it is. When researchers separated people from their iPhones, the poor phone-deprived souls performed worse on cognitive tasks. What’s more, if participants’ iPhones rang while they were in another room and were therefore unable to answer, participants’ heart rates and blood pressure levels increased, they underperformed on simple word-search puzzles, and they reported feeling anxious and “unpleasant,” according to the study. “Our findings suggest that iPhone separation can negatively impact performance on mental tasks,” Russell Clayton, a doctoral candidate at the MU School of Journalism and lead author of the study, said in a statement. “Additionally, the results from our study suggest that iPhones are capable of becoming an extension of ourselves such that when separated, we experience a lessening of ‘self’ and a negative physiological state.” To come to this conclusion, the researchers told participants that they were testing the reliability of a new wireless blood pressure cuff. They asked participants to WORK word search puzzle while they took readings of the participants’ heart rates and blood pressure levels. Then, they took their iPhones away, telling the participants that the phones were causing “Bluetooth interference” with the wireless blood pressure cuff. The iPhones were placed in a nearby room while participants completed a second word-search puzzle. Researchers again recorded their heart rates and blood pressure levels, according to the study. While participants were working their way through the second puzzle, the researchers called the participants’ iPhones. The participants, unable to answer, were clearly vexed: They had significantly higher heart rates and blood pressure levels after the ringing stopped, and were significantly less adept at solving the word-search puzzles. They also reported higher levels of anxiety and feeling higher levels of “unpleasantness” than when they were completing puzzles with their iPhones in their possession, though they were not asked to clarify what aspect of the situation contributed to this feeling. But the research, published Friday in the Journal of Computer-Mediated Communication, opens a whole new can of worms about how closely we associate our cellphones with ourselves. As the 3/2 study puts it, the findings show that people are “capable of perceiving their iPhone as an object of their extended self, which can be negatively impacted (i.e., lessening of self) during separation.” 1. What is/are the independent variable(s) in this study? For each variable you list, also say what type of variable it is. 2. What is/are the dependent variable(s) in this study? For each variable you list, also say what type of variable it is. 3. Is this an observational study or an experiment? How do you know? 4. What are the experimental units for this study? 5. Are there any factors in use here? If so, give the levels of each factor.