Question

Professor Louzine is studying the writing ability of middle-school children. She is concerned that different backgrounds, exposure to different reading materials, and parental educational levels might influence the results of her study. To minimize these potential pre-existing variables, she should be sure to do which of the following?

1) use random assignment when forming her groups
2) include a dependent variable
3) assign boys to the experimental group and girls to the control group
4) include an independent variable

Answer 1

To minimize the influence of different backgrounds in her study on writing ability, Professor Louzine should use random assignment to form her groups, ensuring any lurking variables are equally distributed and only the independent variable is systematically varied.

Step-by-step explanation:

Professor Louzine is concerned that different backgrounds might affect her study on the writing ability of middle-school children. To minimize the impact of potential pre-existing variables, such as varying reading materials and parental educational levels, she should use random assignment when forming her groups. This method ensures any lurking variables are equally distributed across the experimental and control groups, allowing the study to more accurately determine if the observed outcomes are due to the manipulated independent variable rather than other factors.

Random assignment is a critical component in the design of controlled experiments. It helps to ensure that there is only one systematic difference between the comparison groups: the treatment given. Thus, any differences observed in the dependent variable can be attributed to the independent variable's manipulation, providing evidence of a cause-and-effect relationship.