Question

A case-control study of foodborne acute gastroenteritis was conducted during an outbreak. Eating raw seafood was investigated as an exposure. There were 165 cases. The odds ratio was 2.0, the 95% confidence interval was 0.9 to 6.0 and the p-value was 0.2. The significance level for the study was 0.05.

1) Write an interpretation for the 95% confidence interval. (2 points)

2) Is the odds ratio statistically significant (different than 1.0)? Explain why you think that the odds ratio is or is not statistically significant. (2 points)

Answer 1

1. Interpretation for Confidence interval :

In this study the Confidence level is 95% , that means the researcher can say with 95% confidence, the measurements or the resultant parameters are between 0.9 to 6.0. The study very much says that there is a strong association between raw seafood consumption and the incidence of Acute gastroenteritis.  

2. The odds ratio is statistically significant as the value is 2.0. If the odd ratio is < 1, then there is no significant association between risk factors and outcome. If it is 1 , then there is neutral association or no relative risk. If the odds ratio is > 1, then the Relative risk in the case control study is high. In this study as the OR is 2.0 , the relative risk for getting Gastroenteritis is high with the  consumption of Raw sea food. The study is statistically significant.