Question

A clinical trial was conducted (Van Dongen et al. [10]) among children 1-10 years of age with prior symptoms of otorrhea comparing efficacy of () antibiotic eardrops, (i) oral antibiotics, and (ii) observation without treatment, referred to below as observation. Children were seen at home by study physicians at 2 weeks and 6 months after randomization. The primary outcome was the presence of otorrhea at 2 weeks observed by study physicians. The results are given in Table 10.22. TABLE 10.22 Number of children with otorrhea at 2 weeks of follow-up Number of children with otorrhea at 2 weeks Group Number of children Antibiotic ear drops Oral antibiotics Observation 76 4 34 75 9 Provide a point estimate nd a 95% con-dence teral for the prevalence of otorrkea at 2 weeks o the observatvon group. 10 Pro de a point e ate and a 95% for the preva ence of otorrhea ip the ear drop group. 1021 Wh otorrhea for the ear drop group vs. the observation group? State thé hypotheses to be tested. at test can be used to compare the prevalence of 22 Perform the test in Problem 10.21 and report a p-value (two-tailed). Interpret your results in words.

Answer 1

10.21) Chi-Squared goodness of fit test can be conducted to compare the prevalence of otorrhea for the eardrop group vs. the observation group.

Hypothesis to be conducted

Null hypothesis:The presence of otorrhea is observed at 2 weeks.

Alternative Hypothesis: The presence of otorrhea is not observed at 2 weeks.

	Positive Otorrhea	No Otorrhea	Total
Antibiotic ear drops	4	72	76
Observation	41	34	75
	45	106	151

10.22) The contingency table below provides the following information: the observed cell totals and (the expected cell totals)

	Category 1	Category 2	Marginal Row Totals
Group 1	4   (22.65)	72   (53.35)	76
Group 2	41   (22.35)	34   (52.65)	75
Marginal Column Totals	45	106	151    (Grand Total)

The chi-square statistic is 44.0402. The p-value is . This result is significant at p < .05. We reject null hypothesis and we conclude that The presence of otorrhea is not observed at 2 weeks.