EAS100 Lecture Notes - Lecture 11: Random Variable, Fair Coin, Standard Deviation

• School: University of Alberta
• Department: Earth and Atmospheric Sciences
• Course: EAS100
• Professor: Jeffrey Kavanaugh

Document Summary

A variable x is a random variable (rv) if its value depends on the outcome of a random event. We use a capital letter, like x, to denote a random variable. A particular value of a random variable will be denoted with a lower case letter, in this case x. X = number of observed tail while tossing a coin 10 times. X = survival time after specific treatment of a randomly selected patient. X = sat score for a randomly selected college applicant. Similar as for variables in sample data, rvs can be categorical or quantitative, and if they are quantitative, they can be either discrete or continuous. Similar to data description, the models for rvs depend entirely on the type the rv. The models for continuous rvs will be different than those for discrete rvs. Discrete random variables can take one of a finite number of distinct outcomes. The number of stores in a shopping mall.