The Random Selection Experiment Method

When researchers need to select a representative sample from a larger population, they often utilize a method known as random selection. In this selection process, each member of a group stands an equal chance of being chosen as a participant in the study.

Random Selection vs. Random Assignment

How does random selection differ fromrandom assignment? Random selection refers tohow the sample is drawn从人口整体，随机分配是指的how the participants are then assignedto either the experimental or control groups.

It is possible to have both random selection and random assignment in an experiment. Imagine that you use random selection to draw 500 people from a population to participate in your study.

You then use random assignment to assign 250 of your participants to acontrol group(the group that does not receive the treatment or independent variable) and you assign 250 of the participants to the experimental group (the group that receives the treatment or independent variable). Why do researchers utilize random selection? The purpose is to increase the generalizability of the results.

Factors Involved

Imagine that a researcher is selecting people to participate in a study. In order to pick participants, they might choose people using a technique that is the statistical equivalent of a coin toss.

他们可能首先使用随机选择来选择从中绘制参与者的地理区域。然后，他们可能会使用相同的选择过程来选择城市，社区，家庭，年龄范围和个人参与者。

当样本大小很小时，一个不寻常的参与者可以整体对样品具有过度影响。使用更大的样本大小倾向于稀释不寻常的参与者的影响，并防止它们偏斜结果。