Name______________________Section______________________STA 200 Lab41. To test the effectiveness of nicotine patches on the cessation of smoking, Dr. Richard Hurt and hiscolleagues (Hurt et al., 23 February 1994 as cited in Utts) recruited 240 smokers at Mayo Clinics in Rochester, Minnesota; Jacksonville, Florida; and Scottsdale, Arizona. Volunteers were required to be between the ages of 20 and 65, have an expired carbon monoxide level of 10 ppm or greater (showing that they were indeed smokers), be in good health, have a history of smoking at least 20 cigarettes per dayfor the past year, and be motivated to quit.Volunteers were randomly assigned to receive either 22 mg nicotine patches or patches containing no active ingredients for 8 weeks. Neither the participants nor the nurses taking the measurements knew who received the nicotine patches. They were also provided with an intervention program recommended by the National Cancer Institute, in which they received counseling before, during, and after the 8-week period of wearing the patches.After the 8-week period of patch use, almost half (46%) of the group wearing nicotine patches had quit smoking, whereas only one-fifth (20%) of the other group had. Having quit was defined as “self-reportedabstinence (not even a puff) since the last visit and an expired air carbon monoxide level of 8 ppm or less.” (p. 596). After a year the percent who had quit in both groups had declined, but the group that had received the nicotine patch still had a higher percentage who had successfully quit than did the other group: 27.5% versus 14.2%. This study was funded by a grant from Lederle Laboratories and published in the Journal of the American Medical Association. (edited from Utts, 76-77)a. What is the population?all smokers from 20-65, good health, at least a pack per day, and motivated to quitb. What is the sample?240 volunteers who met the characteristics of the population stated in a.c. Is this an experiment or an observational study?experiment since we manipulated levels of nicotine in the patchesd. What is the explanatory variable?amount of nicotine in the patch OR whether or not an active patch was given to the patiente. What is the response variable?smoking status at the end of 8 weeks then again at the end of 1 yearf. What is the treatment?amount of nicotine in the patchg. What is the placebo used?a patch with no nicotine in ith. What is the control group?group that received the placebo patchi. What is a possible interacting variable?indoor/outdoor job, family member who smokes, stress leve.j. Is this study blind, double blind, or neither?double blind since neither the patients or nurses knew which treatment the patients were receiving2. A simple random sample of 20 college students included 10 females and 10 males. Each student was asked to list their own height and the heights of their mother and father. The heights of their parents were averaged to calculate a new variable called Parent Average Height. a. What is the explanatory variable?parent’s average heightb. What is the response variable?student’s heightSTA 200 Lab4 p23. What is a confounding variable and why is it bad?a confounding variable is an “unobserved explanatory variable.” It is bad because in an experiment, we are trying to determine the cause-effect relationship between our “observed” explanatory variable and the response variable. If however, we have a confounding variable, then we will never really be sure whetherchanges in the response variable were caused by the observed explanatory variable or whether the changes were caused by the confounding variable or both.4. For each set of variables listed below, identify which variable should be the response variable and which should be the explanatory variable.a. V1: the amount of money earned for a part-time job - responseV2: the number of hours worked - explanatoryb. V1: the weight of a package - explanatoryV2: the first-class postage rate at the post office - responsec. V1: the salary of a high school teacher - responseV2: the number of years of teaching experience - explanatory5. In a recent article entitled "Shed these food myths: Butter, eggs, starches aren't villains; vitamins, milk,diet pop aren't heroes", the following research study was presented: Research done at the Harvard School of Public Health showed that regular sodadrinkers may have a tendency toward the weak and brittle bones associated withosteoporosis. They surveyed 2,622 women who were active athletes in college andclassified them as to whether they regularly drank soft drinks or rarely drank soft drinks.The proportion of women in each group who suffered from bone fractures wasdetermined. The findings: those who regularly drank soft drinks were twice as likely tosuffer from bone fractures as those who rarely drank soft drinks. --- SOURCE: Healthand Fitness News Service, August 21, 1996. (a) Was this an observational study or an experiment? Explain.This was an observational study since the woman were observed/surveyed. (b) What was the population under study? women who were former athletes (c) What was the explanatory variable? amount of soft drink usage (values are regularly or rarely) (d) What was the response variable?bone health (e) Suppose the 2,622 selected women were obtained as follows: From a list of all women sports events(e.g. tennis, basketball, etc.) available at UK, three events were selected at random. All alumniwomen athletes who participated in these three events were contacted for the study. What type ofsampling technique is described? Can you think of any potential problems with this sampling plan? This sampling plan was a cluster sample since they randomly selected sport events and then surveyed all athletes within that event. The problem with this type of design is that the health and body type of the different sports can vary widely and so if a study happened to randomly sample tennis, track, and soccer this will be much different than if the sample was softball, weightlifting, and volleyball. Stratafied sampling would help the final sample to be more representative of all types of athletes.STA 200 Lab4 p36. Researchers examined the records of a large number of cancer patients. Some patients received an invasive treatment while others received a noninvasive treatment.