/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 3 Marijuana Use and Bone Density I... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Marijuana Use and Bone Density In a 2017 study reported in The American Journal of Medicine, Sophocleous et al. studied 170 adults who smoked marijuana regularly and 114 adults who had never used the drug and found that people who regularly smoke large amounts of marijuana may be more susceptible to bone fractures than people who don't use the drug. Was this a controlled experiment or an observational study? Explain.

Short Answer

Expert verified
This was an observational study. The researchers made observations on two naturally occurring groups without controlling or manipulating any variables.

Step by step solution

01

Analyze the Exercise Statement

Read the exercise statement carefully. Here, Sophocleous et al. studied 170 adults who smoked marijuana regularly and 114 adults who had never used the drug to determine an association, if any, between marijuana use and bone density.
02

Identify Type of Study Involved

Based on the information provided in the exercise statement, we need to identify whether the study in question was a controlled experiment or an observational study. In this case, the researchers observed two naturally occurring groups without any manipulation of variables, which suggests an observational study rather an experiment.
03

Justification

Finally, justify the classification. In this study, the researchers made observations on two groups but did not actively apply or control any variables which is characteristic of an observational study.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Marijuana Use
Marijuana, also known as cannabis, is a commonly used psychoactive substance, with its use spanning both recreational and medicinal purposes. In recent years, its legalization in various regions has provided researchers the opportunity to delve deeper into its effects on human health.

Previous findings have opened discussions surrounding marijuana's potential impact on various aspects of wellbeing, from mental health to cognitive functions. Of particular interest to health researchers are the physiological changes that might arise from regular usage. This includes potential alterations to bone health, an area where research is still emerging. Studies like that of Sophocleous et al. aim to shed light on such associations by observing regular users and non-users.

Understanding these effects is crucial, but it's important to note the limitations that arise from the types of studies conducted. Observational studies, for instance, suggest associations but do not establish causation, necessitating further research to derive definitive conclusions.
Bone Density
Bone density refers to the amount of bone mineral in bone tissue, which determines the strength and rigidity of bones. It's a critical measure for assessing the risk of fractures and the diagnosis of osteoporosis. Factors such as age, genetics, nutrition, physical activity, and hormone levels can influence bone density.

When researchers aim to study factors affecting bone health, they often look at bone density as an endpoint. For instance, in the Sophocleous et al. study, the comparison of bone density between regular marijuana users and non-users aimed to explore whether an association exists between marijuana use and bone health.

The concern here lies in whether substances like marijuana might affect the body's ability to maintain or increase bone density, potentially putting users at risk of bone fractures. However, correlation does not equal causation, and findings from such studies must be interpreted with caution.
Statistical Association
Statistical association is a relationship between two variables such that when one variable changes, the other variable tends to change in a specific way. It's a core concept in research that helps in identifying patterns that may suggest a link between different factors, like marijuana use and lower bone density.

It is important to differentiate between association and causation. An association does not imply that one variable is the cause of changes in another; other variables, known as confounders, may be at play. In studies like those focusing on marijuana use, findings of statistical associations are an important first step but must be followed by more in-depth research to establish any causal links.

Discovery of a statistical association is essential as it helps to identify areas that warrant further research through controlled experiments to explore the nature of the relationship and to establish cause and effect.
Research Design
Research design is the overall strategy that researchers follow to integrate the different components of the study in a coherent and logical way, ensuring that the research problem is effectively addressed. It lays out the blueprint for the collection, measurement, and analysis of data.

Research designs fall into two primary categories: observational studies and controlled experiments. In observational studies, such as the one by Sophocleous et al., researchers observe subjects in a natural setting without influencing the outcome. The objectivity and passive role of the observer are fundamental characteristics of this design.

On the other hand, controlled experiments involve active manipulation of variables to observe their direct effects. They typically offer stronger evidence for causation but can be more costly and ethically challenging to conduct in certain domains, such as substance use. Choice of research design profoundly affects the conclusions that can be drawn from a study.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Late-Onset Schizophrenia Treatment Very late onset schizophrenia affects people who are at least 60 years old. In a 2018 study reported in The Lancet Psychiatry, researchers conducted a double-blind controlled experiment to study the effect of the drug amisulpride on these patients (Howard et al., 2018). The experiment was divided into two stages, and subjects were randomly assigned to one of three groups: Group 1 received the drug for both stages, Group 2 received the drug for stage 1 and the placebo for stage 2 , and Group 3 received the placebo for state 1 and the drug for stage 2. Researchers found that those subjects receiving the drug showed reduced psychosis symptoms compared with those receiving the placebo. a. Identify the treatment and response variables. b. Restate the conclusion of the study in terms of a cause-and-effect conclusion. Why can a cause-and-effect conclusion be made from this study?

Melanoma In a study published in The New England Journal of Medicine, researchers investigated the effectiveness of the drug pembrolizamab on increasing survival rates in patients with advanced melanoma (Eggermont et al. 2018). In this randomized double-blind study, 514 patients received the drug and 505 patients received a placebo. Recurrence-free survival rates for both groups were measured after 15 months. After 15 months, 388 patients in the drug group and 308 patients in the placebo group experienced recurrence-free survival. a. Find and compare the percentages that experienced recurrence-free survival. b. Test the hypothesis that a greater proportion of patients taking the drug experienced recurrence-free survival than those taking the placebo. Use a significance level of \(0.05\). c. Based on this study, do you think the drug pembrolizamab may be effective in treating patients with advanced melanoma? Explain.

Recidivism Rates The 3-year recidivism rate in the United States is about \(68 \%\), which means that \(68 \%\) of released U.S. prisoners return to prison within 3 years of release. There have been many attempts to reduce the recidivism rate. Suppose you want to determine whether electronic monitoring bracelets that track the location of the released prisoner reduce recidivism. Suppose that offenders released from prison are observed for 3 years to see whether they go back to prison and that the ones who wear electronic monitoring bracelets wear them for the first year only. a. Describe a study based on a sample of released offenders that would allow the legal system to conclude that monitoring causes a reduction in recidivism but would not allow it to generalize this result to all released prisoners. b. Describe a study based on a sample of released offenders that does not allow the legal system to conclude that monitoring causes a reduction in recidivism but does allow it to generalize to all released offenders. c. Describe a study based on a sample of released prisoners that allows the legal system to conclude that monitoring causes a reduction in recidivism and also allows it to generalize to all released offenders.

Ketamine and Social Anxiety Disorder (Example 7) According to the National Institute of Mental Health, Social Anxiety Disorder (SAD) is a mental health disorder that affects up to \(7 \%\) of the population of the United States. Because many SAD patients experience inadequate symptom relief with available treatments, researchers in this study investigated the use of ketamine to treat SAD patients (Taylor et al. 2018 ). Read the following excerpts from the study abstract and evaluate the study using the given questions. Methods: We conducted a double-blind, randomized, placebo-controlled crossover trial in 18 adults with Social Anxiety Disorder and compared the effects between intravenous ketamine and placebo on social phobia symptoms. Ketamine and placebo infusions were administered in a random order with a 28 -day washout period between infusions. Ratings of anxiety were assessed 3 -hours post-infusion and followed for 14 days. Outcomes were blinded ratings on the Liebowitz Social Anxiety Scale (LSAS) and self-reported anxiety on a visual analog scale (VAS-Anxiety). Results: We found ketamine resulted in a significantly greater reduction in anxiety relative to placebo on the LSAS \((p=0.01)\) but not the VAS-Anxiety \((p=0.95)\). Participants were significantly more likely to exhibit a treatment response after ketamine infusion relative to placebo in the first 2 weeks following infusion measured on the LSAS \((33.33 \%\) response ketamine vs \(0 \%\) response placebo, \(p=0.025\) ) and VAS \((88.89 \%\) response ketamine vs \(52.94 \%\) response placebo, \(p=0.034)\). Conclusion: This trial provides initial evidence that ketamine may be effective in reducing anxiety.

Professors A college administrator wants to determine whether the professors at the college are doing a good job. Each professor teaches multiple classes, and so for each professor, one of his or her classes is randomly chosen, and all the students are surveyed to find out their opinion of the teacher. What kind of sampling is this?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.