Hypothesis Testing and Variable Types Quiz
68 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What effect would raising the cutoff score for a screening test have on the positive predictive value?

  • It would decrease (correct)
  • It would remain unchanged
  • It would fluctuate
  • It would increase

    • In a population where the prevalence of the disease in question is low, what impact would this have on the positive predictive value of a screening test?

  • It would remain unchanged
  • It would decrease (correct)
  • It would increase
  • It would fluctuate

    • If the cutoff score for a screening test is lowered, what impact would this have on the positive predictive value?

  • It would remain unchanged
  • It would fluctuate
  • It would increase (correct)
  • It would decrease

    • What measure of association would be most appropriate to calculate in this scenario?

    <p>Odds ratio</p> Signup and view all the answers

    What is the impact of raising the cutoff score for a screening test on the sensitivity of the test?

    <p>It decreases</p> Signup and view all the answers

    What test would be most suitable to test the statistical significance of the association?

    <p>Chi-square test</p> Signup and view all the answers

    In which scenario would you expect the positive predictive value of a screening test to be higher?

    <p>In a population with high disease prevalence</p> Signup and view all the answers

    What would be the null hypothesis in this scenario?

    <p>There is no association between exposure and outcome</p> Signup and view all the answers

    What is one advantage of conducting a case-control study rather than a cohort study in this scenario?

    <p>Less prone to recall bias</p> Signup and view all the answers

    Why would there be difficulty in concluding a causal relationship in this study, even if a strong association is found between administration of the measles vaccine and preterm births?

    <p>Potential confounding factors</p> Signup and view all the answers

    What type of test did the researchers use to study the association and reject the null hypothesis?

    <p>Chi-square test</p> Signup and view all the answers

    Which variable type is used for labeling theatre-goers as youth, regular adult, or seniors?

    <p>Nominal</p> Signup and view all the answers

    Which variable type is used for coding UW students as '0' if an undergraduate student or '1' if a graduate student?

    <p>Dichotomous/Binary</p> Signup and view all the answers

    What analytical plan would be suitable for knowing the mean difference in hospital charges between persons with and without Medicaid?

    <p>Two-sample t-test</p> Signup and view all the answers

    How would you decide whether you can reject the null hypothesis in the context of analyzing hospital charges between persons with and without Medicaid?

    <p>By comparing p-values to the significance level</p> Signup and view all the answers

    What is the sensitivity of the ELISA test for detecting HIV antibody?

    <p>94.0%</p> Signup and view all the answers

    What type of study design would be most appropriate for investigating the association between preterm births and the measles vaccine?

    <p>Case-control study</p> Signup and view all the answers

    What is the specificity of the ELISA test for detecting HIV antibody?

    <p>98.0%</p> Signup and view all the answers

    In which study design is the study sample selected on the basis of outcome status?

    <p>Case-control study</p> Signup and view all the answers

    What is the actual prevalence of HIV antibody in the hypothetical patient population?

    <p>1.0%</p> Signup and view all the answers

    Which study design would be most suitable for studying the incidence rate of a disease in the exposed and non-exposed?

    <p>Cohort study</p> Signup and view all the answers

    What are false positives in the context of screening for HIV antibody using the ELISA test?

    <p>Individuals who do not have HIV antibody but are incorrectly identified as positive by the test</p> Signup and view all the answers

    In which study design are the results especially prone to recall bias?

    <p>Case-control study</p> Signup and view all the answers

    What are false negatives in the context of screening for HIV antibody using the ELISA test?

    <p>Individuals who have HIV antibody but are incorrectly identified as negative by the test</p> Signup and view all the answers

    Which study design involves randomly assigning participants to either be exposed to a treatment or not exposed?

    <p>Neither</p> Signup and view all the answers

    What is the significance of the confidence interval not including 0?

    <p>It indicates a statistically significant result</p> Signup and view all the answers

    When reporting the median as the measure of central tendency, what should also be reported?

    <p>Interquartile range</p> Signup and view all the answers

    What type of graph is typically used to depict a distribution?

    <p>Histogram</p> Signup and view all the answers

    Which statements about the distribution in the histogram are true?

    <p>It is right skewed</p> Signup and view all the answers

    Which measures of central tendency and spread would be best to report for the variable depicted in the histogram?

    <p>Median and interquartile range</p> Signup and view all the answers

    What does it mean if the confidence interval around the mean difference includes zero?

    <p>The result is not statistically significant</p> Signup and view all the answers

    What is the prevalence of anti-social behaviors at the time of study enrollment?

    <p>40%</p> Signup and view all the answers

    Can the incidence of anti-social behaviors during the study period (9th-12th grade) be calculated?

    <p>Yes, it can be calculated</p> Signup and view all the answers

    What is the main strength of a screening tool with high specificity but low sensitivity?

    <p>It minimizes false positives</p> Signup and view all the answers

    What is a key limitation of a screening tool with low sensitivity?

    <p>It may generate many false negatives</p> Signup and view all the answers

    What would be a recommended implementation for a screening tool with high specificity but low sensitivity in elementary schools?

    <p>Use it as an initial broad screening tool and follow up with more sensitive tests for positive cases</p> Signup and view all the answers

    What does the sensitivity of a screening test measure?

    <p>The proportion of positive tests that are truly positive.</p> Signup and view all the answers

    Which factor leads to a marked increase in the positive predictive value of a test?

    <p>Higher prevalence in the screened population</p> Signup and view all the answers

    Which term refers to the ability of a test to identify correctly those who do not have the disease?

    <p>Specificity</p> Signup and view all the answers

    What does the negative predictive value measure?

    <p>The proportion of negative tests that are truly negative.</p> Signup and view all the answers

    Which factor determines the positive predictive value of a test?

    <p>The prevalence of the disease in the population tested</p> Signup and view all the answers

    What does specificity measure for a screening test?

    <p>The proportion of negative tests that are truly negative.</p> Signup and view all the answers

    Which is true about Positive Predictive Value (PPV)?

    <p>PPV increases with a higher prevalence in the screened population.</p> Signup and view all the answers

    What does the null hypothesis (Ho) in hypothesis testing typically state?

    <p>There is no difference, effect, or association</p> Signup and view all the answers

    In hypothesis testing, what does the alternative hypothesis (Ha) usually represent?

    <p>Researchers' ideas to be proven</p> Signup and view all the answers

    What is the significance level (α) used for in hypothesis testing?

    <p>To decide the rejection region</p> Signup and view all the answers

    What is the primary purpose of the rejection region in hypothesis testing?

    <p>To decide the statistical significance</p> Signup and view all the answers

    In hypothesis testing, what is the primary purpose of the z-tabulated value?

    <p>To decide significance</p> Signup and view all the answers

    What is the alternative hypothesis (Ha) in Case 1 of the provided examples?

    <p>Well water at the fair was the risk factor/source of diarrheal disease.</p> Signup and view all the answers

    What is the null hypothesis (Ho) in Case 3 of the provided examples?

    <p>Mean birthweight in counties implemented starting right is equal with the mean weight birthweight in non-starting right implemented counties.</p> Signup and view all the answers

    What does the significance level (α) typically represent?

    <p>(1-confidence level)</p> Signup and view all the answers

    What is the definition of Incidence Rate?

    <p>The number of new cases of a disease that occur in a population at risk per person-time of observation</p> Signup and view all the answers

    What is the Bathtub Analogy used to illustrate?

    <p>The relationship between prevalence and incidence</p> Signup and view all the answers

    What is the key measure used in screening tests to correctly identify those who have the disease?

    <p>Sensitivity</p> Signup and view all the answers

    What does a true negative (TN) represent in the context of screening tests?

    <p>People who do not have the disease and have a negative test result</p> Signup and view all the answers

    What does the positive predictive value (PPV) measure in screening tests?

    <p>The proportion of true positives out of all those with a positive test result</p> Signup and view all the answers

    What impact does raising the cutoff score for a screening test have on sensitivity?

    <p>Decreases sensitivity</p> Signup and view all the answers

    What represents a false positive (FP) in the context of screening tests?

    <p>People who have a positive test result but do not have the disease</p> Signup and view all the answers

    What is the key goal of using screening tests?

    <p>To reduce morbidity and mortality</p> Signup and view all the answers

    What does a Relative Risk (RR) value greater than 1 indicate?

    <p>Higher incidence of disease in the exposed group</p> Signup and view all the answers

    How is the Relative Risk (RR) interpreted when it equals 1?

    <p>No association, or no difference in incidence of disease between the two exposure groups</p> Signup and view all the answers

    In the context of Relative Risk (RR), what does it mean if non-smokers have '1.6 times less risk' of developing CHD than smokers?

    <p>Non-smokers have a lower risk compared to smokers</p> Signup and view all the answers

    What is the interpretation of a Relative Risk (RR) value less than 1?

    <p>Lower incidence of disease in the unexposed group</p> Signup and view all the answers

    What would be the most suitable interpretation of a Relative Risk (RR) value equal to 1?

    <p>No association, or no difference in incidence of disease between the two exposure groups</p> Signup and view all the answers

    According to the measure of association, what does a numerator of 'Risk of disease in exposed' represent?

    <p>People at risk of developing a disease and exposed to a specific factor</p> Signup and view all the answers

    In the context of Relative Risk (RR), what does a denominator of 'Risk of disease in unexposed' represent?

    <p>People at risk of developing a disease but not exposed to any factor</p> Signup and view all the answers

    How would you interpret a Relative Risk (RR) value equal to 1?

    <p>'No difference between exposed and unexposed groups'</p> Signup and view all the answers

    'Smokers have a 1.6 times greater risk of developing CHD than non-smokers'. What is the inverse true statement?

    <p>'Non-smokers have 60% decreased risk of CHD compared to smokers'</p> Signup and view all the answers

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser