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The San Luis Obispo Tribune (May 7, 2002) reported that “a new analysis has found that in the majority of trials conducted by drug companies in recent decades, sugar pills have done as well as—or better than—antidepressants.” What effect is being described here? What does this imply about the design of experiments with a goal of evaluating the effectiveness of a new medication?
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- What is an experiment?arrow_forwardThis problem is based on information taken from The Merck Manual (a reference manual used in most medical and nursing schools). Diltiazem is a commonly prescribed drug for hypertension. However, diltiazem causes headaches in about 12% of patients using the drug. It is hypothesized that regular exercise might help reduce the headaches. If a random sample of 205 patients using diltiazem exercised regularly and only 15 had headaches, would this indicate a reduction in the population proportion of patients having headaches? Use a 1% level of significance. 1. What is the value of the sample test statistic? (Round your answers to two decimal places.) 2. Find the P-value of the test statistic. (Round your answers to four decimal places.)arrow_forwardIn the early 1970s, a young man challenged an Oklahoma state law that prohibited the sale of 3.2% beer to males under age 21 but allowed its sale to females in the same age group. The case (Craig v. Boren, 429 U.S. 190, 1976) was ultimately heard by the U.S. Supreme Court. The state of Oklahoma argued that the law improved traffic safety. One of the three main pieces of data presented to the court was the result of a “random roadside survey.” This survey gathered information on gender and whether or not the driver had been drinking alcohol in the previous 2 hours. A total of 619 drivers under 21 years of age were included in the survey. The chi-square test statistic is approximately 1.64 for this data. Find the P-value State a conclusion at a 5% level of significance. Do you think that the data supports the Oklahoma law that forbids sale of 3.2% beer to males and permits it to females? See image.arrow_forward
- This problem is based on information taken from The Merck Manual (a reference manual used in most medical and nursing schools). Diltiazem is a commonly prescribed drug for hypertension. However, diltiazem causes headaches in about 11% of patients using the drug. It is hypothesized that regular exercise might help reduce the headaches. If a random sample of 206 patients using diltiazem exercised regularly and only 17 had headaches, would this indicate a reduction in the population proportion of patients having headaches? Use a 1% level of significance. (a) What is the level of significance?State the null hypothesis H0 and the alternate hypothesis H1 . H0 : p H1 : p (b) What sampling distribution will you use? The standard normalThe Student's t since np and nq What is the value of the sample test statistic? (Round your answers to two decimal places.)(c) Find the P-value of the test statistic. (Round your answers to four decimal…arrow_forwardA researcher is interested in the impact of joining a weight loss program in the past 12 months on the individuals weight loss. The analysis is restricted to people aged 16 and older who answered yes to the question "During the past 12 months, have you tried to lose weight?" About 5% of the sample had joined a weight loss program in the past year. Below is a subset of some of the other variables included in the survey. Questions were asked about actions taken in the past 12 months. Which ones do you believe should be included as covariates? Provide a justification for your choice. Age BMI Gendere Height Average minutes of exercise per week whether they tried to eat less calories whether they tried to eat less fat whether they tried to eat less carbsarrow_forwardIt appears that there is some truth to the old adage “That which doesn’t kill us makes us stronger.” Seery, Holman, and Silver (2010) found that individuals with some history of adversity report better mental health and higher well-being compared to people with little or no history of adversity. In an attempt to examine this phenomenon, a researcher surveys a group of college students to determine the negative life events that they experienced in the past 5 years and their current feeling of well-being. For n = 16 participants with 2 or fewer negative experiences, the average well-being score is M = 42 with SS = 398, and for n = 16 participants with 5 to 10 negative experiences the average score is M = 48.6 with SS = 370. Is there a significant difference between the two populations represented by these two samples? Use a two-tailed test with α = .01 [use the 4-step procedure]. [Remember to assess whether the assumption of homogeneity of variances is satisfied or not, alpha = .01…arrow_forward
- It appears that there is some truth to the old adage “That which doesn’t kill us makes us stronger.” Seery, Holman, and Silver (2010) found that individuals with some history of adversity report better mental health and higher well-being compared to people with little or no history of adversity. In an attempt to examine this phenomenon, a researcher surveys a group of college students to determine the negative life events that they experienced in the past 5 years and their current feeling of well-being. For n = 18 participants with 2 or fewer negative experiences, the average well-being score is M = 42 with SS = 398, and for n = 16 participants with 5 to 10 negative experiences the average score is M = 48.6 with SS = 370. a.) Is there a significant difference between the two populations represented by these two samples? Include whether you reject or retain the Null Hypothesis. Use a two-tailed test with α = 0.01 b.) Compute Cohen’s d to measure the size of the effect. c.) Write a…arrow_forwardAn industrial/organizational psychologist has been consulting with a company that runs weekend job-seeking workshops for the unemployed. He collected data on several issues related to these workshops and, after conducting statistical tests, obtained statistically significant findings. He needs to find a way to evaluate effect size so that he can make recommendations to the company. One of the psychologist’s findings is that six months after the workshop, a sample of 49 job seekers who received training on resume writing scored an average of 6.5 as measured on a 9-point job-search satisfaction scale, with a standard deviation of 1.2. The typical job seeker scores 5.8 points. The psychologist finds that the estimated Cohen’s d is ____ , the t statistic is 4.12, and r² is . Using Cohen’s d and Cohen’s guidelines for interpreting the effect size with the estimated Cohen’s d, there is a _____ treatment effect. Using r² and the extension of Cohen’s guidelines for interpreting…arrow_forwardWhat benefit does conducting an experiment to prove that free coffee causes more frequent shoe purchases have beyond determining cause and effect? An experiment allows the researcher to include as many variables as possible in the experiment . An experiment allows the researcher to cross -check that their observations are correct . This type of study allows a researcher to employ a case study research design . An experiment allows the researcher to eliminate the effects of confounding variablesarrow_forward
- A past issue of The Journal News (Hamilton, Ohio) reported on a study conducted by the Kaiser Family Foundation regarding parents' use of television set V-chips for controlling their childrens' TV viewing. The study asked parents who own TVs equipped with V-chips whether they use the devices to block programs with objectionable content.a. Suppose that we wish to use the study results to justify the claim that fewer than 20 percent of parents who own TV sets with V-chips use the devices. The study actually found that 17 percent of the parents polled used their V-chips. If the poll surveyed 1,000 parents, and if for the sake of argument we assume that 20 percent of parents who own V-chips actually use the devices (that is, p = .2), calculate the probability of observing a sample proportion of .17 or less. That is, calculate ?(?≤.17).b. Based on the probability you computed in part a, would you conclude that fewer than 20 percent of parents who own TV sets…arrow_forwardAn industrial/organizational psychologist has been consulting with a company that runs weekend job-seeking workshops for the unemployed. She collected data on several issues related to these workshops and, after conducting statistical tests, obtained statistically significant findings. She needs to find a way to evaluate effect size so that she can make recommendations to the company. One of the psychologist’s findings is that immediately after the workshop, a sample of 81 job seekers who received training on using the Internet to find job listings worked more than 30 hours per week an average of 8.7 months in the last year, with a standard deviation of 4.1. The typical job seeker works 7.4 months. The psychologist finds that the estimated Cohen’s d is , the t statistic is 2.83, and r² is . Using Cohen’s d and Cohen’s guidelines for interpreting the effect size with the estimated Cohen’s d, there is a treatment effect. Using r² and the extension of Cohen’s guidelines…arrow_forwardDo sports drinks help prevent cramps in endurance sports? At the end of a marathon, officials will ask runners if they drank water or a sports drink during the race, along with whether or not they suffered any cramps. Is this an observational study or experiment?arrow_forward
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