/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 2 If two events \(A\) and \(B\) ar... [FREE SOLUTION] | 91Ó°ÊÓ

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If two events \(A\) and \(B\) are independent and you know that \(P(A)=0.3,\) what is the value of \(P(A | B) ?\)

Short Answer

Expert verified
\(P(A | B) = 0.3\) because events \(A\) and \(B\) are independent.

Step by step solution

01

Understand Independent Events

Two events are independent if the occurrence of one does not affect the probability of the occurrence of the other. This implies that if events \(A\) and \(B\) are independent, the probability of \(A\) given \(B\) is simply the probability of \(A\).
02

Apply the Definition of Independent Events

Since events \(A\) and \(B\) are independent, we have \(P(A | B) = P(A)\). This means that knowing \(B\) occurred doesn't change the probability of \(A\) occurring.
03

Use Given Probability

We are given that \(P(A) = 0.3\). Therefore, by the property of independent events, \(P(A | B) = 0.3\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Conditional Probability
Conditional probability is the likelihood of an event occurring given that another event has already occurred. It provides a way to update our predictions about an event using new information. Mathematically, conditional probability is defined as the probability of event A given event B, and is denoted by \( P(A | B) \). The formula for conditional probability is:\[P(A | B) = \frac{P(A \cap B)}{P(B)}\]This formula expresses how frequently A happens given B. In cases where events are dependent, the occurrence of one alters the probability of the other. However, in this particular problem, since events A and B are stated as independent, conditional probability simplifies. The occurrence of B does not affect the probability of A.
Probability of Independent Events
In probability theory, two events are said to be independent if the occurrence or non-occurrence of one does not influence the occurrence of the other. This is a crucial concept as it simplifies the computation of probabilities when dealing with multiple events.
  • The probability of two independent events A and B occurring together is the product of their probabilities: \( P(A \cap B) = P(A) \cdot P(B) \).
  • For independent events, knowing that event B has occurred provides no additional information about the likelihood of event A occurring.
This results in the important relationship \( P(A | B) = P(A) \), which was directly applied in the given original exercise. Understanding whether events are independent or not can significantly impact how you approach probability calculations in various contexts.
Understanding Probability
Probability is the mathematical study of randomness and uncertainty. It provides a systematic method to quantify uncertainty and make informed predictions based on available data.
  • Basic probability ranges from 0 to 1, where 0 indicates impossibility, and 1 indicates certainty.
  • It involves the calculation of how likely an event or a range of events is to occur.
Understanding probability involves recognizing patterns, deducing relationships between events, and applying this to real-world data and scenarios. By knowing the concepts of conditional probability and the independence of events, one can better grasp how to manage and predict outcomes based on given conditions. Whether it's flipping a coin, rolling dice, or deciding policy responses, probability forms the backbone of rational decision-making that accounts for uncertainty.

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Most popular questions from this chapter

Survey: Customer Loyalty Are customers more loyal in the east or in the west? The following table is based on information from Trends in the United States, published by the Food Marketing Institute, Washington, D.C. The columns represent length of customer loyalty (in years) at a primary supermarket. The rows represent regions of the United States. $$\begin{array}{lccccccc} \hline & \begin{array}{c} \text { Less Than } \\ \text { 1 Year } \end{array} & \begin{array}{c} 1-2 \\ \text { Years } \end{array} & \begin{array}{c} 3-4 \\ \text { Years } \end{array} & \begin{array}{c} 5-9 \\ \text { Years } \end{array} & \begin{array}{c} 10-14 \\ \text { Years } \end{array} & \begin{array}{c} 15 \text { or More } \\ \text { Years } \end{array} & \begin{array}{c} \text { Row } \\ \text { Total } \end{array} \\ \hline \text { East } & 32 & 54 & 59 & 112 & 77 & 118 & 452 \\ \text { Midwest } & 31 & 68 & 68 & 120 & 63 & 173 & 523 \\ \text { South } & 53 & 92 & 93 & 158 & 106 & 158 & 660 \\ \text { West } & 41 & 56 & 67 & 78 & 45 & 86 & 373 \\ \text { Column Total } & 157 & 270 & 287 & 468 & 291 & 535 & 2008 \\ \hline \end{array}$$ What is the probability that a customer chosen at random (a) has been loyal 10 to 14 years? (b) has been loyal 10 to 14 years, given that he or she is from the east? (c) has been loyal at least 10 years? (d) has been loyal \(a t\) least 10 years, given that he or she is from the west? (e) is from the west, given that he or she has been loyal less than I year? (f) is from the south, given that he or she has been loyal less than 1 year? (g) has been loyal I or more years, given that he or she is from the east? (h) has been loyal I or more years, given that he or she is from the west? (i) Are the events "from the east" and "loyal 15 or more years" independent? Explain.

Lisa is making up questions for a small quiz on probability. She assigns these probabilities: \(P(A)=0.3, P(B)=0.3, P(A \text { and } B)=0.4\) What is wrong with these probability assignments?

Basic Computation: Multiplication Rule Given \(P(A)=0.7\) and \(P(B)=0.8.\) (a) If \(A\) and \(B\), are independent events, compute \(P(A \text { and } B).\) (b) If \(P(B | A)=0.9,\) compute \(P(A \text { and } B).\)

The qualified applicant pool for six management trainee positions consists of seven women and five men. (a) How many different groups of applicants can be selected for the positions? (b) How many different groups of trainees would consist entirely of women? (c) Probability Extension If the applicants are equally qualified and the trainee positions are selected by drawing the names at random so that all groups of six are equally likely, what is the probability that the trainee class will consist entirely of women?

Education: College of Nursing At Litchfield College of Nursing, \(85 \%\) of incoming freshmen nursing students are female and \(15 \%\) are male. Recent records indicate that \(70 \%\) of the entering female students will graduate with a BSN degree, while \(90 \%\) of the male students will obtain a BSN degree. If an incoming freshman nursing student is selected at random, find (a) \(P(\text { student will graduate } |\) student is female). (b) \(P(\) student will graduate and student is female). (c) \(P(\text { student will graduate } |\) student is male). (d) \(P(\) student will graduate and student is male). (e) \(P(\) student will graduate). Note that those who will graduate are either males who will graduate or females who will graduate. (f) The events described by the phrases "will graduate and is female" and "will graduate, given female" seem to be describing the same students. Why are the probabilities \(P\) (will graduate and is female) and \(P\) (will graduate I female) different?

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