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Using the addition rule for probability, we will show you how to find the probability of the union of two events. We will use the table below about students who are gifted and those who are not. What is the probability that a randomly chosen student is gifted or male? First, we need to know […]

When you get the probability of the intersection of two events, we call this probability joint probability. Let A and B be two events in a sample space. The intersection of A and B is the collection of all outcomes that are common to both A and B. We can denote the intersection of A […]

In this lesson, you will learn to compute the probability of complementary events. What are complementary events though? Let A be an event. The complement of A consists of all outcomes in which event A does not occur. The symbol that we use to denote the complement of A is the following: A and  the complement […]

In this lesson, we will do the following using a table that shows test results for 200 students who took a GED test. Let us start with the probability of independent events. Consider the following table. Let pass be the event that a randomly selected student has passed the test Let male be the event that […]

Mutually exclusive events are events that cannot occur together. In other words these events do not have any common outcomes. Consider the following 2 events when throwing a die once. Let B = an even number is observed Let A = an odd number is observed B  = { 2, 4, 6 }     […]

To find the conditional probability, we will use the contingency table that we used in the lesson about marginal probability The table shows test results for 200 students who took a GED test. From the list of 200 students, we select a student randomly . However, suppose that you already know the student selected if […]

To explain what marginal probability is, we need a contingency table. A contingency table is a table in which we show frequency for 2 variables. One variable is used to categorize rows and the other is used to categorize columns. Suppose a company specializes in training students to pass the GED test. The company had […]

What is probability? How to calculate probability? We will answer these questions here along with some useful properties of probability. Probability is a numerical measure of the likelihood that a specific event will occur. For a simple event E1, the likelihood of E1 happening is denoted by P(E1) For a compound event A, the likelihood […]

Before we show you the difference between simple and compound events, we will start with a definition of event. Event   If the event has only 1 outcome, the event is called a simple event. A simple event is usually denoted by E1, E2, E3, E4, and so forth.  Any other capital letter could be […]

A sample space diagram is a diagram used to describe a sample space.  But what is a sample space? A concrete example will make it easy to understand. Suppose you toss a coin twice. The result is shown below. HH HT TH TT   The terms below in bold are important terms that you need […]