New "closed loop" (CL) devices have been developed to help to suppress overactive brain activity in patients with conditions such as Parkinson's disease and epilepsy.† The CL device is implanted directly into a specific area of the brain, and one of the key advantages is that it can immediately apply a treatment in reaction to heightened brain activity. This may help to reduce the duration of seizures and other periods of uncontrolled movement in patients. A study was conducted on the effectiveness of the CL device on brain activity in rats. First, each of seven rats was observed for 15 minutes with the CL device implanted but not activated (OFF). The percentage of the time that each rat was moving was recorded. Then, after each CL device was activated (CL), the percentage of the time that the rat was moving was recorded over another 15-minute period. The OFF and CL data values given in the accompanying table are approximated from a graph in the research article. The calculated difference in movement, OFF − CL, is also given. What is the P-value? Rat ID OFF CL Difference (OFF − CL) 1 97.8 56.6 41.2 2 56.9 25.5 31.4 3 57.7 40.0 17.7 4 58.1 68.1 −10.0 5 49.8 45.1 4.7 6 53.1 35.7 17.4 7 57.8 44.5 13.3

An interesting experiment was described in the paper "Sociochemosensory and Emotional Functions."† The authors of this paper wondered if college students could recognize their roommate by scent. They carried out an experiment in which female college students used fragrance-free soap, deodorant, shampoo, and laundry detergent for a period of time. Their bedding was also laundered using a fragrance-free detergent. Each person was then given a new t-shirt that she slept in for one night. The shirt was then collected and sealed in an airtight bag. Later, the roommate was presented with three identical t-shirts (one worn by her roommate and two worn by other women) and asked to pick the one that smelled most like her roommate. (Yes, hard to believe, but people really do research like this!) This process was repeated a second time, with the shirts refolded and rearranged before the second trial. The researchers recorded how many times (0, 1, or 2) that the shirt worn by the roommate was…

Researchers are interested in testing the effectiveness of a new immunosuppressive therapy to be used post-transplant to reduce graft failure in the host. Suppose researchers investigating this new therapy are concerned about the dangerous side-effects of the drug. For instance, participants that would like to enroll in the study are not allowed to already have diabetes, as the immunosuppressive agent has been found to drastically increase fasting glucose levels, which could be very dangerous for diabetics. This means, however, that participants that enter and are treated with the new drug may develop diabetes as time goes on. Suppose the following table addresses the incidence of diabetes in the study depending on treatment group. (α=.01)     Type II Diabetes No Type II Diabetes Total Investigational Drug 45 32 77 Best standard of Care 35 50 85 Total 80 82 162   Based on this information complete the hypothesis steps for Chi-Squared below:…

Another researcher also decides to conduct a study to observe the association between smoking cessation among long-term smokers and obesity since it has been previously well documented in the literature that smokers tend to gain weight when they stop smoking. The researcher notes that among the individuals who gain weight, many of them have developed heart problems or other medical problems that typically prevent them from exercising as much as their counterparts. In this case the researcher notes that individuals who have developed the heart problems or other medical problems causing them to gain weight also came from family with a high prevalence of risk-taking behaviors so they consume unhealthy diets and are less likely to exercise in general than their counterparts. This is an example of which of the following? Multilpe Choice Confounding   Effect modification   Recall bias   Socially desirable response bias

Employee’s human capital is measured in terms of his/her age, education, tenure, and rank. Number of years an employee worked in the same organization measures the amount of firm-specific human capital that employee possesses. Data of 413 employees’ tenure was analyzed to predict interim leadership role importance in a study reported in Journal of Advanced Management Research (Vol. 9, 2012). The following table shows the data of these employees tenure in the organization: Tenure (in years) 0-1 1-6 6-11 11-20 20-21 No. of employees 48 109 58 75 123 Calculate mean tenure of these 413 employees.

A sociologist of education wants to prove that students’ sense of mastery and control before a math test could increase if students had a chance to practice with examples of questions from typical tests. The sociologist has long studied sense of content’s mastery and emotional control pre-math test with a scale called NoStressM, which ranges from 0 to 50, where 0 indicates great stress, and 50 indicates great control and mastery. In the typical student population, the day before the math test, students score 20 points on average, with a standard deviation of 6 points. The sociologist selected at a random a sample of 60 students from different schools and 3 offered them to practice for a week with questions drawn from typical math tests. The day before the math test, she administered the NoStressM scale to the 60 students and found a sample mean of 23 and a standard deviation like the one in the population. Your turn: a) Formulate the null and the alternative hypotheses that fit this…

An interesting experiment was described in the paper "Sociochemosensory and Emotional Functions."† The authors of this paper wondered if college students could recognize their roommate by scent. They carried out an experiment in which female college students used fragrance-free soap, deodorant, shampoo, and laundry detergent for a period of time. Their bedding was also laundered using a fragrance-free detergent. Each person was then given a new t-shirt that she slept in for one night. The shirt was then collected and sealed in an airtight bag. Later, the roommate was presented with three identical t-shirts (one worn by her roommate and two worn by other women) and asked to pick the one that smelled most like her roommate. (Yes, hard to believe, but people really do research like this!) This process was repeated a second time, with the shirts refolded and rearranged before the second trial. The researchers recorded how many times (0, 1, or 2) that the shirt worn by the roommate was…

To test compliance with authority, a classical experiment in social psychology requires subjects to administer increasingly painful electric shocks to seemingly helpless victims who agonize in an adjacent room.* Each subject earns a score between 0 and 30, depending on the point at which the subject refuses to comply with authority—an investigator, dressed in a white lab coat, who orders the administration of increasingly intense shocks. A score of 0 signifies the subject's unwillingness to comply at the very outset, and a score of 30 signifies the subject's willingness to comply completely with the experimenter's orders.   Ignore the very real ethical issues raised by this type of experiment, and assume that you want to study the effect of a “committee atmosphere” on compliance with authority. In one condition, shocks are administered only after an affirmative decision by the committee, consisting of one real subject and two associates of the investigator, who act as subjects but, in…

Imagine you need to come up with a diagnostic test to monitor the viral load of patients with HIV. If the viral load is higher than a set standard, there is evidence the anti-retroviral therapy is no longer working and the patient needs to be moved to a different therapy that costs more money. Thus, false positives incur higher costs. However, if the test misses higher than normal viral loads (for patients in treatment), then the patient runs the risk of developing AIDS. Hence, false negatives result in a likely deadly disease. How would you balance these two types of error in devising your test? Minimize beta by raising the one-tailed alpha, since greater power will reduce false negatives and save patients O Minimize the one-tailed alpha, since lower P-values indicate the test is highly significant and prevent prematurely switching the patients Minimize the one-tailed alpha and beta, since this action will prevent prematurely switching the patients and reduce false negatives, thereby…

Beryllium is an extremely lightweight metal that is used in many industries, such as aerospace and electronics. Long-term exposure to beryllium can cause people to become sensitized. Once an individual is sensitized, continued exposure can result in chronic beryllium disease, which involves scarring of the lungs. In a study of the effects of exposure to beryllium, workers were categorized by their duration of exposure (in years) and by their disease status (diseased, sensitized, or normal). The results were as follows:     Duration of Exposure   <1 1 to <5 ≥5 Diseased 14 13 18 Sensitized 11 20 15 Normal 78 140 209 Test the hypothesis of independence. Use the a=0.10 level of significance and the P-value method with the TI-84 Plus calculator. What do you conclude? State the null and alternate hypotheses.