Quiz3
frmncktopx002
week10_quiz.docxQUESTION 1
· Which of the following is not associated with an increased likelihood for the odds ratio to approximate the true rate ratio associated with the exposure in the underlying population while undergoing a case-control study?
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· a. When incidence measures are used to investigate the relationship |
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· b. When incidence-density sampling is used |
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· c. When ascertainment of exposure status is nonbiased in selection of cases and controls |
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· d. When the disease is rare |
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QUESTION 2
· There is a direct relationship between the chi-square and the standard normal distributions, whereby the square root of each chi-square statistic is mathematically equal to the
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· a. corresponding r statistic at significance level α. |
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· b. corresponding q statistic at significance level α. |
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· c. corresponding F statistic at significance level α. |
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· d. corresponding z statistic at significance level α. |
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QUESTION 3
· The Chi-Square analysis provides researchers with a specific estimate of the overall significance for the relationship between an outcome and a categorical exposure variable when there are more than 2 categories,
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· a. in order to assess the individual relationships, researchers should calculate individual risk ratios. |
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· b. the individual relationships are expressed by the overall risk ratios. |
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· c. in order to assess the individual relationships, researchers should divide the overall risk ratio. |
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· d. in order to assess the individual relationships, researchers should multiply the overall risk ratio. |
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QUESTION 4
· Naturalistic Samples. Are
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· a. Fixed numbers of individuals selected according to the outcome variable. |
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· b. Fixed numbers of individuals selected according to the explanatory factor. |
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· c. An SRS with data then cross-classified according to the explanatory variable and response variable. |
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· d. All individuals in a population. |
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QUESTION 5
· Purposive Cohort Samples.
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· a. Fixed numbers of individuals selected according to the outcome variable. |
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· b. Fixed numbers of individuals selected according to the explanatory factor. |
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· c. An SRS with data then cross-classified according to the explanatory variable and response variable. |
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· d. All individuals in a population. |
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QUESTION 6
· Case-Control Samples.
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· a. Fixed numbers of individuals selected according to the outcome variable. |
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· b. Fixed numbers of individuals selected according to the explanatory factor. |
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· c. An SRS with data then cross-classified according to the explanatory variable and response variable. |
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· d. All individuals in a population. |
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QUESTION 7
· The continuity-corrected or Yate’s method compared to Pearson’s
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· a. produces larger chi-square statistics and larger smaller P -values. |
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· b. produces smaller chi-square statistics and larger P-values |
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· c. produces larger chi-square statistics and larger P-values |
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· d. produces smaller chi-square statistics and smaller P-values |
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QUESTION 8
· Which of the following statements is not correct?
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· a. It is necessary to supplement chi-squares with measures of association. |
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· b. Chi-square statistics do not measure the strength of association. |
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· c. One should use descriptive statistics or RRs to quantify “strength.” |
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· d. It is not necessary to supplement chi-squares with measures of association. |
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QUESTION 9
· When observed values = expected values, the chi-square statistic is ?
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· a. 0 |
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· b. 1 |
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· c. -1 |
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· d.Infinity |
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QUESTION 10
· Do not use a chi-square test when more than 20% of the cells have expected values that are less than?
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· 20 |
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· b. 100 |
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QUESTION 11
· Matched-pair samples, where each participant is carefully matched to a unique individual as part of the selection process, is appropriate for
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· a. Only case control studies |
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· b. Only cohort studies |
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· c. Both case control or cohort studies |
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· d. Never |
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QUESTION 12
· To test H0: OR = 1 in a matched pairs sample use
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· a. McNemar’s test statistic. |
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· b. T-test statistic |
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· c. F test statistic |
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· d. Western blot test |
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QUESTION 13
· Investigators interested in the association between serum vitamin D levels and various birth outcomes recruited pregnant mothers to have a blood draw during the second trimester of their pregnancy. Mothers were followed until they gave birth. The health outcomes were compared among mothers with low, adequate, and high vitamin D levels. This an example of a _______ sampling method?
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· a. Case control |
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· b. cohort |
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· c. Simple Random Sample |
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· d. D) Complexity science |
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QUESTION 14
· Describe a risk measurement that you think would be most appropriate to compare the groups in the previous example.
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· a. Odds Ratio |
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· b. Pearson’s r |
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· c. Relative risk |
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· d. Fisher’s exact test |
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QUESTION 15
· In order to investigate the relationship between dietary aflatoxins and hepatocellular carcinoma (HCC), all cases of liver cancer developed in the past five years and liver cancer-free controls selected from a pre-existing study cohort at the time of diagnosis were included in the analysis. The exposure of interest, aflatoxins, was assessed from dietary recall questionnaires collected from the subjects at the beginning of the study. Describe a risk measurement that you think would be most appropriate to compare the groups.
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· a. Odds Ratio |
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· b. Pearson’s r |
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· c. Relative risk |
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· d. Fisher’s exact test |
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