Concept explainers
Effectiveness of a New Drug. As part of the U.S. Food and Drug Administration’s approval process, a new rheumatoid arthritis drug was compared to a placebo. The randomized, double-blind study with 482 patients showed that 41% of those given the new drug had a decrease in symptoms, while 19% of those given the placebo experienced improvement (Western Journal of Medicine).
a. Which patients were in the treatment group and the control group?
b. Do the results appear to offer evidence that the new drug was effective? Why or why not?
c. Do the results appear to indicate that a placebo effect was present in these trials? Explain.
d. If you were on the panel deciding whether to approve the new drug, how would you vote based on this study? Explain your reasoning.
Want to see the full answer?
Check out a sample textbook solutionChapter 5 Solutions
USING+UNDERSTANDING MATH.(LL)-W/MYMATH.
- What is an experiment?arrow_forwardWhat is meant by the sample space of an experiment?arrow_forwardDoes ginkgo improve memory? The law allows marketers of herbs and other natural substances to make health claims that are not supported by evidence. Brands of ginkgo extract claim to “improve memory and concentration.” A randomized comparative experiment found no statistically significant evidence for such effects. The subjects were 350 healthy volunteers over 60 years old. They were randomly assigned to ginkgo or a placebo pill (a dummy pill that looks and tastes the same). All the subjects took a battery of tests for learning and memory before treatment started and again after six weeks. (a) The study was double-blind. Why is this important? (b) Can the results of this study be generalized to a larger population? Can cause-and-effect be inferred? Explain. (c) Explain why it is advantageous to use 350 volunteers in this study, rather than, say, 30.arrow_forward
- ) Name one other limitation in this study (do not repeat any of the limitations you may have named above in your previous answers) and suggest how you would improve it.arrow_forwardDoes heavy cell phone use affect brain activity? There is some concern about possible negative effects of radiofrequency signals delivered to the brain. In a randomized matched-pairs study, 47 healthy participants had cell phones placed on the left and right ears. Brain glucose metabolism (a measure of brain activity) was measured for all participants under two conditions: with one cell phone turned on for 50 minutes (the “on” condition) and with both cell phones off (the “off” condition). The amplitude of radio frequency waves emitted by the cell phones during the “on” condition was also measured. Is this an example of “paired-samples” or “independent samples”? The investigators were interested in seeing whether average brain glucose metabolism was different based on whether the cell phones were turned on or off. State the null and alternative hypotheses for this test. Suppose that the mean of differences ? is 0.8, ignoring the unit for now, and the standard deviation of the…arrow_forwardA sports psychologist studied the effect of a motivational program on number of injuries in one year among players of three different sports (baseball, football, and basketball). Players were randomly assigned to one of two conditions: either participate in a motivational program or none (control). Data was collected on the number of injuries sustained by each athlete that season. Question: If p = .024 for the main effect of sports, what should the researcher conclude?arrow_forward
- AD (Alzheimer's disease) causes progressive cognitive impairment. A diagnostic blood test for AD was proposed. An evaluation of the blood text involved fifty known AD patients and forty control who did not have AD. Of those who had AD, forty eight tested positive on the blood test and two tested negative. Of those without AD, three tested positive on the blood test and thirty seven tested negative. d. With a serious disease, it is important that a very high proportion of those who have the disease be detected by the test? Was this the case here? What the name for the proportion is of cases that are detected by a test?arrow_forwardAs men age, their testosterone levels gradually decrease. This may cause a reduction in energy, an increase in fat, and other undesirable changes. Do testosterone supplements reverse some of these effects? A study in the Netherlands assigned 237 men aged 60 to 80 with low or low-normal testosterone levels to either a testosterone supplement or a placebo. Why is it necessary to include a control group in this experiment? Every experiment needs a control group in order to make proper comparisons between treatments. A control group is necessary to balance the effects of other variables among the treatment groups. A control group is necessary so any differences in the effects of the treatments can be distinguished from chance differences between the groups. A control group helps avoid confounding and reduces variability in the response variable. A control group is used to provide a baseline for comparing the effects of other treatments.arrow_forward"Does ginkgo improve memory?" The law allows marketers of herbs and other natural substances to make health claims that are not supported by evidence. Brands of ginkgo extract claim to "improve memory and concentration." A randomized experiment found some statistically significant evidence for such effects. The subjects were 250 healthy volunteers over 65 years old. They were randomly assigned to take ginkgo or a placebo pill (a dummy pill that looks and tastes the same). All the subjects took a battery of tests for learning and memory before treatment started and again after six weeks. a). The article said the study was double-blind. What does this mean in the context of this study? Be very specific on who's being blinded and explain why they should be blinded. b). You suspect physical fitness and mental fitness go hand-in-hand. Create a flow chart to describe a design for an experiment to include the confounding variable physical fitness. Be very specific in your design. Include all…arrow_forward
- Vasectomies and Prostate Cancer. In the United States, approximately 450,000 vasectomies are performed each year. In this surgical procedure for contraception, the tube carrying sperm from the testicles is cut and tied. Several studies have been conducted to analyze the relationship between vasectomies and prostate cancer. The results of one such study by E. Giovannucci et al. appeared in the paper “A Retrospective Cohort Study of Vasectomy and Prostate Cancer in U.S. Men” (Journal of the American Medical Association, Vol. 269(7), pp. 878–882). Of 21,300 men who had not had a vasectomy, 69 were found to have prostate cancer; of 22,000 men who had had a vasectomy, 113 were found to have prostate cancer. a. At the 1% significance level, do the data provide sufficient evidence to conclude that men who have had a vasectomy are at greater risk of having prostate cancer? Consider men who had had a vasectomy Population 2. b. Is this study a designed experiment or an observational study?…arrow_forwardA behavioral scientist investigated whether there is a significant difference in the percentages of men and women who purchase silver-colored cars. The scientist selected a random sample of 50 men and a random sample of 52 women who had recently purchased a new car. Of the men selected, 16 had purchased a silver-colored car. Of the women selected, 9 had purchased a silver-colored car. Which of the following is the most appropriate method for analyzing the results? A two-sample zz-test for the difference in population proportions A A two-sample zz-test for the difference in sample proportions B A one-sample zz-test for a sample proportion C A one-sample zz-test for a population proportion D A one-sample zz-test for a difference in sample proportionsarrow_forwardDoes being part of a support group affect the ability of people to quit smoking? A county health department enrolled 300 smokers in a randomized experiment. 150 participants were assigned to a group that used a nicotine patch and met weekly with a support group; the other 150 received the patch and did not meet with a support group. At the end of the study, 40 of the participants in the patch plus support group had quit smoking while only 30 smokers had quit in the other group. (a) Create a two-way table presenting the results of this study. (b) Answer each of the following questions under the null hypothesis that being part of a support group does not affect the ability of people to quit smoking, and indicate whether the expected values are higher or lower than the observed values. i. How many subjects in the “patch + support” group would you expect to quit? ii. How many subjects in the “patch only” group would you expect to not quit?arrow_forward
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin HarcourtGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning