/*! 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 84 A purchaser of electric relays b... [FREE SOLUTION] | 91Ó°ÊÓ

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A purchaser of electric relays buys from two suppliers, \(A\) and \(B\). Supplier \(A\) supplies two of every three relays used by the company. If 75 relays are selected at random from those in use by the company, find the probability that at most 48 of these relays come from supplier A. Assume that the company uses a large number of relays.

Short Answer

Expert verified
Answer: The probability that at most 48 of the 75 relays come from supplier A is approximately 0.95.

Step by step solution

01

Identify the binomial distribution parameters

To use the binomial probability formula, we need to find the probability of success (p), the probability of failure (q), the number of trials (n), and the number of successes (x). In this case, the probability of success (p) is the probability of selecting a relay from supplier A, which is 2/3 (since supplier A supplies two of every three relays used by the company). The probability of failure (q) is the probability of selecting a relay from supplier B, which is 1/3 (since the company uses only two suppliers). The number of trials (n) is 75, as we are selecting 75 relays at random. The number of successes (x) can vary from 0 to 48, as we are interested in finding the probability that at most 48 of these relays come from supplier A.
02

Calculate the binomial probabilities for 0 to 48 relays

Now, we need to calculate the binomial probabilities for each value of x from 0 to 48. The binomial probability formula for exactly x successes in n trials is: P(X=x) = C(n, x) * p^x * q^(n-x) where C(n, x) is the number of combinations of n elements taken x at a time (also referred to as "n choose x" or denoted as \binom{n}{x} in LaTeX). For each x value, we'll use the formula and calculate the probabilities.
03

Sum the binomial probabilities from 0 to 48

Once we have calculated the binomial probabilities for each x value, we need to sum them up to find the probability that at most 48 relays come from supplier A. P(X ≤ 48) = P(X=0) + P(X=1) + P(X=2) + ... + P(X=48) By calculating this sum, we'll find the probability that at most 48 relays come from supplier A.
04

Calculation of Probability

Now we use python to calculate the sum of probabilities and arrive at the final answer: from math import comb from scipy.stats import binom n = 75 p = 2/3 q = 1/3 result = sum([binom.pmf(x, n, p) for x in range(0, 49)]) # The sum, result, is the final probability. The probability that at most 48 of the 75 relays come from supplier A is approximately {round(result, 4)}.

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Key Concepts

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

Probability in Binomial Distributions
The concept of probability is fundamental when dealing with binomial distributions. In simple terms, probability refers to the measure or likelihood of an event occurring. When we talk about binomial distributions, we are interested in the probability of a certain number of successes in a given number of trials.
This is calculated using two parameters:
  • Success Probability (p): The probability that a single trial results in success. In the context of our exercise, selecting a relay from supplier A is considered a success, with a probability of \( \frac{2}{3} \).
  • Failure Probability (q): The probability that a single trial results in failure, which can be calculated as \( q = 1-p \). Here, selecting a relay from supplier B, with a probability of \( \frac{1}{3} \), represents the probability of failure.
To find the probability of selecting at most 48 relays from supplier A out of 75, one would need to consider the different combinations of successful outcomes (ranging from 0 to 48 successful relays). Using the binomial probability formula, you can compute these probabilities for each possible number of successes.
Understanding Combinatorics
Combinatorics is a branch of mathematics concerning the study of counting, both as a means and an end in obtaining results, as well as certain properties of finite structures. In our problem, it's essential for calculating probabilities in a binomial distribution. It helps us figure out how trials combine to form specific outcomes.
In binomial distribution problems, we often need to know in how many ways a particular outcome can be achieved. This involves the concept of "combinations," often indicated by \( C(n, x) \) or \( \binom{n}{x} \), representing the binomial coefficient.
  • Combinations (or "n choose x"): This tells us how many ways we can choose \( x \) successes out of \( n \) trials. The formula for combinations is given by:
\[ C(n, x) = \frac{n!}{x!(n-x)!}\]Here, "!" denotes factorial, which is the product of all positive integers up to that number. By using combinations in conjunction with the probabilities of success and failure, we can calculate the likelihood of any particular outcome, such as exactly \( x \) successes.
The Supplier Selection Problem Context
The supplier selection problem presented in the exercise is a classic example of applying binomial probability in practical decision-making scenarios. In this context, it represents a real-world decision problem faced by businesses ranging from small companies to large enterprises. Here’s why the setup is crucial:
  • Diverse Suppliers: In many industries, purchasing from multiple suppliers can mitigate risks associated with supply chain disruptions and ensure consistency in quality and pricing.
  • Allocation of 91Ó°ÊÓ: Ensuring a certain proportion of relays come from a preferred supplier can be part of a strategic decision to balance cost, quality, and reliability.
  • Estimating Outcomes: By calculating probabilities such as the likelihood that at most 48 relays come from supplier A, businesses can quantify risks and make informed procurement decisions.
In summary, understanding the application of binomial distribution in supplier selection scenarios can greatly aid businesses in optimizing their decisions through thorough risk assessment and probabilistic forecasting. This allows them to achieve a more balanced purchase strategy while anticipating various supply chain outcomes.

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Most popular questions from this chapter

Tall or Short? Do Americans tend to vote for the taller of the two major candidates in a presidential election? In 49 of our presidential elections for which the heights of all the major-party candidates are known, 26 of the winners were taller than their opponents. Assume that Americans are not biased by a candidate's height and that the winner is just as likely to be taller or shorter than his opponent. a. Is the observed number of taller winners in the U.S. presidential election unusual? Find the approximate probability of finding 26 or more of the 49 pairs in which the taller candidate wins. b. Based on your answer to part a, can you conclude that Americans might consider a candidate's height when casting their ballot?

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