/*! 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 22 Assume that when adults with sma... [FREE SOLUTION] | 91Ó°ÊÓ

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Assume that when adults with smartphones are randomly selected, \(54 \%\) use them in meetings or classes (based on data from an LG Smartphone survey). If 20 adult smartphone users are randomly selected, find the probability that exactly 15 of them use their smartphones in meetings or classes.

Short Answer

Expert verified
The probability is 0.1285.

Step by step solution

01

- Understand the problem

We need to find the probability that exactly 15 out of 20 selected adults use their smartphones in meetings or classes, given that 54% of adults use them in such scenarios.
02

- Identify the type of problem

This is a binomial probability problem where we need to find the probability of a certain number of successes (people using smartphones in meetings) in a fixed number of trials (total people selected).
03

- Define variables for the binomial probability

Here: - The number of trials, n = 20- The number of successes, k = 15- The probability of success on a single trial, p = 0.54
04

- Write the binomial probability formula

The formula for binomial probability is: \[ P(X = k) = \binom{n}{k} p^k (1-p)^{n-k} \] where \(\binom{n}{k}\) is the binomial coefficient.
05

- Calculate the binomial coefficient

First, compute \(\binom{n}{k}\) where \(\binom{n}{k} = \frac{n!}{k!(n-k)!} \):\( \binom{20}{15} = \frac{20!}{15!5!} = 15504 \).
06

- Compute the probabilities

Calculate \( p^k \) and \( (1-p)^{n-k} \):\( p^k = 0.54^{15} \) and \( (1-p)^{n-k} = (0.46)^5 \).
07

- Combine into the formula

Multiply the binomial coefficient by the probabilities: \[ P(X = 15) = 15504 \times 0.54^{15} \times 0.46^5 \].
08

- Calculate the final probability

Perform the calculations: \[ 0.54^{15} \approx 3.717 \times 10^{-4} \] and \[ 0.46^5 \approx 0.0453 \]. Multiply all values together: \[ 15504 \times 3.717 \times 10^{-4} \times 0.0453 \approx 0.1285 \].

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Key Concepts

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

binomial distribution
To apply the binomial formula, we need to identify our n (number of trials), k (number of successes), and p (probability of success in one trial). These values are then substituted into the formula for the final calculation.
probability calculation
By following these detailed steps, one can calculate the binomial probability for any similar situation.
binomial coefficient
This coefficient indicates there are 15,504 different ways to arrange 15 successes and 5 failures in twenty trials. Understanding how to compute and interpret this value is key to solving binomial probability problems.
statistics problems
  • Market research: Predicting consumer behavior, like how many people will use a smartphone in specific situations.
  • Medical studies: Determining the probability of patients responding to a treatment.
  • Quality control: Assessing the chance of defects in a batch of products.

In these examples, we can set up a similar structure: specify n (total trials), p (probability of success per trial), and k (desired number of successes) to calculate probabilities using the binomial formula.
Whether predicting the number of successful outcomes in trials or informing decisions based on probability, mastering binomial distributions and calculations is an invaluable statistical skill.

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Most popular questions from this chapter

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