The article “The Effect of Restricting Opening Hours on Alcohol-Related Violence” (S. Duailibi, W. Ponicki, et al., American Journal of Public Health, 2007:2276–2280) presented homicide rates for the years 1995–2005 for the town of Diadema, Brazil. In 2002, a law was passed requiring bars to close at 11 pm each night. After the law’s passage, the homicide rate dropped by an average of 9 homicides per month, a statistically significant decrease. Which of the following is the best conclusion?
- i. It is reasonable to conclude that the law is responsible for a reduction of 9 homicides per month.
- ii. It is reasonable to conclude that the law is responsible for a reduction in homicides, but the actual amount might be somewhat more or less than 9 per month.
- iii. It is reasonable to conclude that the homicide rate decreased, but the law may not have anything to do with the decrease.
- iv. It is plausible that the homicide rate may not have decreased at all after the passage of the law.
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