A study is funded by the tobacco industry to examine the association between smoking and lung cancer. They design a study with a prospective cohort of 1,000 smokers between the ages of 20-30. The length of the study is five years. After the study period ends, they conclude that there is no relationship between smoking and lung cancer. Which of the following study features is the most likely reason for the failure of the study to note an association between tobacco use and cancer?
ALate-look bias
BLatency period
CConfounding
DEffect modification
EPygmalion effect
A research team develops a new monoclonal antibody checkpoint inhibitor for advanced melanoma that has shown promise in animal studies as well as high efficacy and low toxicity in early phase human clinical trials. The research team would now like to compare this drug to existing standard of care immunotherapy for advanced melanoma. The research team decides to conduct a non-randomized study where the novel drug will be offered to patients who are deemed to be at risk for toxicity with the current standard of care immunotherapy, while patients without such risk factors will receive the standard treatment. Which of the following best describes the level of evidence that this study can offer?
ALevel 1
BLevel 3
CLevel 5
DLevel 4
ELevel 2
A neuro-oncology investigator has recently conducted a randomized controlled trial in which the addition of a novel alkylating agent to radiotherapy was found to prolong survival in comparison to radiotherapy alone (HR = 0.7, p < 0.01). A number of surviving participants who took the alkylating agent reported that they had experienced significant nausea from the medication. The investigator surveyed all participants in both the treatment and the control group on their nausea symptoms by self-report rated mild, moderate, or severe. The investigator subsequently compared the two treatment groups with regards to nausea level. | | Mild nausea | Moderate nausea | Severe nausea | |---|---|---|---| | Treatment group (%) | 20 | 30 | 50 | | Control group (%) | 35 | 35 | 30 | Which of the following statistical methods would be most appropriate to assess the statistical significance of these results?
AChi-square test
BPearson correlation coefficient
CMultiple logistic regression
DUnpaired t-test
EPaired t-test
+ 7 more in the PDF
Browse all chapters