/*! 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 50 A particular telephone number is... [FREE SOLUTION] | 91影视

91影视

A particular telephone number is used to receive both voice calls and fax messages. Suppose that \(25 \%\) of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. What is the probability that a. At most 6 of the calls involve a fax message? b. Exactly 6 of the calls involve a fax message? c. At least 6 of the calls involve a fax message? d. More than 6 of the calls involve a fax message?

Short Answer

Expert verified
a. Use binomial CDF for \( P(X \leq 6) \), b. \( P(X = 6) \), c. \( 1 - P(X \leq 5) \), d. \( 1 - P(X \leq 6) \).

Step by step solution

01

Identify Distribution

We are dealing with a scenario where calls are either voice calls or fax messages, which follows a binomial distribution. Let \( X \) represent the number of calls with fax messages out of 25 total calls. Here, \( X \) follows a binomial distribution with parameters \( n = 25 \) and \( p = 0.25 \).
02

Define Probability Notation

For a binomial distribution, the probability of exactly \( k \) successes in \( n \) trials is given by the formula: \[ P(X = k) = \binom{n}{k} p^k (1-p)^{n-k} \]where \( \binom{n}{k} \) is the binomial coefficient defined as \( \frac{n!}{k!(n-k)!} \).
03

Calculate at Most 6 Fax Calls

To find the probability that at most 6 of the calls involve a fax message, we need to compute:\[ P(X \leq 6) = \sum_{k=0}^{6} P(X = k) \]Calculate each probability using the binomial formula and sum them up to find \( P(X \leq 6) \).
04

Compute Exactly 6 Fax Calls

Use the binomial probability formula to find \( P(X = 6) \):\[ P(X = 6) = \binom{25}{6} (0.25)^6 (0.75)^{19} \]Calculate this value to find the probability.
05

Calculate at Least 6 Fax Calls

To calculate \( P(X \geq 6) \), use the complement rule:\[ P(X \geq 6) = 1 - P(X < 6) = 1 - P(X \leq 5) \]Sum probabilities \( P(X = k) \) for all \( k = 0 \) to \( 5 \) and subtract from 1.
06

Compute More Than 6 Fax Calls

Compute \( P(X > 6) \) using:\[ P(X > 6) = 1 - P(X \leq 6) \]We have already calculated \( P(X \leq 6) \), so this completes the calculation.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

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

Probability Calculation
Probability calculation helps us to determine the likelihood of various events occurring in specified conditions. In a binomial distribution setting, probability is used to find how likely a specific number of successes will be out of a given number of trials.

For example, suppose you have a telephone line that receives both voice calls and fax messages. If only 25% of the calls are fax messages, and you want to study 25 calls, you can calculate how probable it is to have a certain number of fax messages in those calls. To find this probability, use the formula related to binomial distribution, which considers both the number of trials (calls) and the desired number of successes (fax messages). By plugging into the formula, you can find the probability for any given number of fax calls among the total.
Binomial Coefficient
The binomial coefficient, often seen denoted as \( \binom{n}{k} \), is a crucial part of determining probabilities in binomial distributions. It tells us how many ways "k" successes can occur in "n" trials. This is commonly used in probability calculations, especially in binomial settings.

To calculate it, the formula \( \binom{n}{k} = \frac{n!}{k!(n-k)!} \) is used, where \(!\) denotes the factorial of a number. For instance, in the scenario of calls where only a fraction are fax calls, the binomial coefficient assists in determining the different ways these calls can happen among the total received calls. Thus, when you want to find the probability of exactly a certain number of fax calls using \( P(X = k) \), you first find the binomial coefficient to aid in your computation.
Complement Rule
The complement rule is a handy probability tool, which states that the probability of an event not occurring is one minus the probability of the event occurring. This rule simplifies calculations in complicated scenarios.

In the provided exercise, the complement rule is used to find probabilities like "at least鈥 or 鈥渕ore than鈥 a certain number of fax calls. For instance, to calculate the probability of receiving at least 6 fax messages, instead of calculating the probability for 6,7,8,...etc., one can calculate the probability for up to 5 fax messages and subtract this from 1. This rule turns otherwise cumbersome calculations into straightforward ones, by converting such scenarios into simpler complementary ones.
Statistical Analysis
Statistical analysis is the process of collecting and interpreting data to gain insights and infer conclusions. In a telephone call scenario, statistical analysis might involve evaluating the distribution of fax versus voice calls.

Using tools like the binomial distribution, you can assess various outcomes and their probabilities. You evaluate collected data (such as calls received) and apply statistical formulas to predict future events or understand patterns within the data. You'll use calculated probabilities to help make informed decisions, such as adjusting staffing levels based on expected call volumes. By looking at how likely different numbers of fax calls are, you can make decisions on resource allocation or further investigate any anomalies or trends in the data.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

An article in the Los Angeles Times (Dec. 3, 1993) reports that 1 in 200 people carry the defective gene that causes inherited colon cancer. In a sample of 1000 individuals, what is the approximate distribution of the number who carry this gene? Use this distribution to calculate the approximate probability that a. Between 5 and 8 (inclusive) carry the gene. b. At least 8 carry the gene.

Give three examples of Bernoulli rv's (other than those in the text).

Organisms are present in ballast water discharged from a ship according to a Poisson process with a concentration of 10 organisms/ \(\mathrm{m}^{3}\) [the article "4 Counting at Low Concentrations: The Statistical Challenges of Verifying Ballast Water Discharge Standards" (Ecological Applications, 2013: 339-351) considers using the Poisson process for this purpose]. a. What is the probability that one cubic meter of discharge contains at least 8 organisms? b. What is the probability that the number of organisms in \(1.5 \mathrm{~m}^{3}\) of discharge exceeds its mean value by more than one standard deviation? c. For what amount of discharge would the probability of containing at least 1 organism be \(.999\) ?

Let \(X\) have a Poisson distribution with parameter \(\mu\). Show that \(E(X)=\mu\) directly from the definition of expected value. [Hint: The first term in the sum equals 0 , and then \(x\) can be canceled. Now factor out \(\mu\) and show that what is left sums to 1.]

A geologist has collected 10 specimens of basaltic rock and 10 specimens of granite. The geologist instructs a laboratory assistant to randomly select 15 of the specimens for analysis. a. What is the pmf of the number of granite specimens selected for analysis? b. What is the probability that all specimens of one of the two types of rock are selected for analysis? c. What is the probability that the number of granite specimens selected for analysis is within 1 standard deviation of its mean value?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.