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?     Confounding     Effect modification     Recall bias     Socially desirable response bias

You are concerned that nausea may be a side effect of Tamiflu, but you cannot just give Tamiflu to patients with the flu and say that nausea is a side effect if people become nauseous. This is because nausea is common for people who have the flu. From past studies you know that about 30% of people who get the flu experience nausea. You collected data on 1744 patients who were taking Tamiflu to relieve symtoms of the flu, and found that 572 experienced nausea. Use a 0.01 significance level to test the claim that the percentage of people who take Tamiflu for the relief of flu symtoms and experience nausea is greater than 30%.a) Identify the null and alternative hypotheses?�0:               �1:               b) What type of hypothesis test should you conduct (left-, right-, or two-tailed)? left-tailed right-tailed two-tailed c) Identify the appropriate significance level.d) Calculate your test statistic. Write the result below, and be sure to round your final answer to two decimal…

Suppose we are interested in studying the relationship between the shelf life of cheeses in a dairy factory and the thickness of the packaging material used for those cheeses. We would like to determine if there is a causal relationship between the thickness of the packaging material and the shelf life of the cheese; that is, does a change in the thickness of the packaging material cause a change in the shelf life of the cheese? Select the study that would be best source of evidence for establishing the existence of a causal relationship. Select one: O a. A study which uses a stratified random sample, stratifying by type of cheese, to select units of cheese in the factory and determine the thickness of the packaging material and test the shelf life of each unit. O b. A study which uses a cluster sample, clustering by room the cheese is stored in, to select units of cheese in the factory and determine the thickness of the packaging material and test the shelf life of each unit. O c. A…

Arthritis is a very commonly occurring affliction. It is a major cause of lost work time and often results in serious disability.  Of the many types of arthritis, the most common type is osteoarthritis.  This condition is frequently due to wear and tear in the joints and is more likely to be found in people over 50.  It is very painful in the weight-bearing joints, such as the knees and hips.  Cartilage wears away on the bone ends, causing pain and swelling.  Osteoarthritis may develop after an injury such as a bone fracture or a joint dislocation.  To reduce the amount of time osteoarthritis patients are absent from work, it is important for them to have effective pain relief.  An experiment was conducted to compare the effectiveness of three new analgesics: A1, A2, and A3.  A clinic evaluated a large group of patients and identified 45 patients with a moderate level of pain.  Fifteen of the 45 persons were then randomly assigned to one of the three analgesics.  The patients were then…

Among the literature on quitting smoking are data detailing the relative successfulness of people of different ages in quitting smoking. A study of 400 adults who began various smoking-cessation programs produced the data in the table below. In the table, each participant is classified according to two variables: length of their smoking cessation period ("Less than two weeks", "Between two weeks and one year", or "At least one year") and age ("21-34", or "35 and over"). In the table, "less than two weeks" means that the individual returned to smoking within two weeks of beginning the program; "between two weeks and one year" means that the individual lasted the first two weeks without smoking but retuned to smoking within a year; and "at least one year" means that the individual has not smoked for at least a year since beginning the program. The table is a contingency table whose cells contain the respective observed frequencies of classifications of the 400 smokers. In addition, three…

Identifying individuals with a high risk of Alzheimer’s disease usually involves a long series of cognitive tests. However, researchers have developed a 7-Minute Screen, which is a quick and easy way to accomplish the same goal. The question is whether the 7-Minute Screen is as effective as the complete series of tests. To address this question, Ijuin et al. (2008) administered both tests to a group of patients and compared the results. The following data represent results similar to those obtained in the study:   Patient            7-Minute         Screen Cognitive Tests  A                            3                           11  B                            8                           19  C                          10                           22  D                            8                          20  E                            4                           14  F                            7                           13  G                           4…