STATS 250 Lecture Notes - Lecture 4: Confounding, Simple Random Sample, Dependent And Independent Variables

• School: U of M
• Department: Statistics
• Course: STATS 250
• Professor: Brenda Gunderson

Document Summary

Observational studies: the researchers simply observe or measure the participants (about opinions, behaviors, or outcomes) and do not assign any treatments or conditions. Experiments: the researchers manipulate something and measure the effect of the manipulation on some outcome of interest. Most studies, either observational or experimental, are interested in learning of the effect of one variable (called the explanatory variable) on another variable (called the response or outcome variable). The effect of a confounding variable on the response variable cannot be separated from the effect of the explanatory variable. Confounding variables might be measured and accounted for in the analysis, or they could be unmeasured lurking variables. Randomized experiments help control the influence of confounding variables. A researcher at the university of michigan believes that the number of times a student visits the. The researcher selected a simple random sample of 100 students from a total of.