Transportation Statistics and Microsimulation

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6Chapter

Sampling Distributions

6.1 INTRODUCTION

In Chapters 4 and 5, we introduced the concepts of probability, random

variables, and the distribution of populations. In probability, it is assumed

that we know the population distribution, and our goal is to nd the prob-

ability, or chance, of observing a particular event. For example, if we know

that crash counts have a Poisson distribution with a known mean value

(λ), we can calculate the relevant probabilities. In statistics, the character-

istics or distribution of the population is oen unknown, and the goal is

to estimate unknown population characteristics, or the distribution based