WBR0742
| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Serge Korjian)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biostatistics/Epidemiology |
| Sub Category | SubCategory::Gastrointestinal |
| Prompt | [[Prompt::A researcher is studying the optimal dose of ranitidine required for relief of gastroesophageal reflux disease symptoms (GERD). He enrolls 240 patients known to have GERD and who complain of have similar symptoms. The patients receive oral ranitidine in 50 mg increments every 24 hours until they reach the dose that provides them with symptomatic relief. Following data collection, the researcher demonstrates his findings on the graph shown below. Based on his findings, which of the following statements regarding the mean, median, and mode is correct?
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| Answer A | [[AnswerA::Median > Mode > Mean]] |
| Answer A Explanation | AnswerAExp::This is not the relationship in positively skewed graphs. |
| Answer B | [[AnswerB::Mode > Median > Mean]] |
| Answer B Explanation | AnswerBExp::This would be a correct answer in negatively skewed graphs. |
| Answer C | [[AnswerC::Mean > Median > Mode]] |
| Answer C Explanation | AnswerCExp::This is the correct relationship between mean, median, and mode in positively skewed graphs. |
| Answer D | [[AnswerD::Mean > Mode > Median]] |
| Answer D Explanation | AnswerDExp::This is not the relationship in positively skewed graphs. |
| Answer E | [[AnswerE::Mode > Mean > Median]] |
| Answer E Explanation | AnswerEExp::This is not the relationship in positively skewed graphs. |
| Right Answer | RightAnswer::C |
| Explanation | [[Explanation::Based on the graph above, the distribution of the researcher's findings show a positively skewed graph because the tail of the graph is towards the positive side. In such graphs, the relationship of the mean, median, and mode are always as follows: mean > median > mode.
In contrast, a negatively skewed graph, where the tail is towards the more negative values, the relationship is always as follows: mode > median > mean. Notably, in both positively and negatively skewed graphs, the median is always in the middle. Graphs with normal distribution typically have mean = median = mode. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Median, WBRKeyword::Mode, WBRKeyword::Mean, WBRKeyword::Skew, WBRKeyword::Skewed, WBRKeyword::Normal distribution |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
