研究研究中的随机样本

当您阅读医学研究时，术语“随机样本”概括了很多。了解这一术语可以帮助您解释您在新闻中遇到的那些健康研究，并更好地掌握它们的可能，也可能不会掌握。

Simply put, a randomsample是个人的一部分randomly selected由研究人员表示整个组。目标是获得一个人的样本representativeof the larger population.

例如，如果研究人员对学习感兴趣alcoholic useamong college students in the United States, the larger population (in other words, the "group of interest"), would be made up of every kid in every college and university in the country. It would be virtually impossible to interview each and every one of these people to find out if they drink, what types of alcohol they drink, how often, under what circumstances, how much (a beer or two per week versus enough to get intoxicated every weekend), and so forth. Instead of undertaking such a gargantuan task, scientists will pull together a random sample of college students to represent the total population of college students.

研究人员如何创建随机样本

随机采样可能是昂贵且耗时的。然而，采集研究数据的这种方法确实提供了将一个真正代表整个组的无偏见样本放在一起的最佳机会。

Going back to the imaginary study of alcohol use among college students, here's how random sampling might work. According to the National Center for Education Statistics ( NCES), approximately 20.2 million students were enrolled in U.S. colleges and universities in 2015, the most recent statistics available. These 20 million-plus individuals represent the total population to be studied.

For the purpose of drawing a random sample of this group, all students must have an equal chance of being selected. For example, scientists conducting the study would need to make sure that the sample included the same percentage of men and women as the larger population. According to the NCES statistics, 11.5 million of the total population of college students are female and 8.7 million are male. The sample group would need to reflect this same ratio of women to men.

Besides gender, researchers would also want to go through the same process for other characteristics—for example, race, cultural background, year in school, socio-economic status, and so forth, depending on the specific purpose of the study. For instance, if they wanted to home in on alcohol use among Asian students, they would create a random sample consisting only of Asian students. By the same token, if the study was focused on how much students drink during the week, they would create a questionnaire or other method for finding only kids who drink on weekdays for their research.