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Introduction to Statistics II - Lecture 4

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Lecture 4 - Discrete Distributions

A student takes a 10 question true-false quiz. Because the student had such a busy schedule, he or she could not study and randomly guesses at each answer. What is the probability of the student passing the test with at least a 70%?

Small companies might be interested in the number of long distance phone calls their employees make during the peak time of the day. Suppose the average is 20 calls. What is the probability that the employees make more than 20 long distance phone calls during the peak time?

These two examples illustrate two different types of probability problems involving discrete random variables. Recall that discrete data is data that you can count. A random variable describes the outcomes of a statistical experiment both in words and numerically. The values of a random variable can vary with each repetition of an experiment.

This lecture covers probability problems involving discrete random distributions. You will also study long-term averages associated with them.

Dr. Barbara Illowsky, Susan Dean
Collaborative Statistics
Date accessed: 2009-01-17
License: Creative Commons Attribution 2.0

Lecture Material

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