Skip to main content
Ch. 5 - Normal Probability Distributions
Larson - Elementary Statistics: Picturing the World 8th Edition
Larson8th EditionElementary Statistics: Picturing the WorldISBN: 9780137493470Non è quello che usi tu?Cambia libro di testo
Capitolo 5, Problema 5.CR.12a

Forty-nine percent of U.S. adults think that human activity such as burning fossil fuels contributes a great deal to climate change. You randomly select 25 U.S. adults. Find the probability that the number who think that human activity contributes a great deal to climate change is (a) exactly 12,

Guida verificata passo dopo passo
1
Step 1: Recognize that this is a binomial probability problem. The binomial distribution is used when there are a fixed number of independent trials (n), each with two possible outcomes (success or failure), and the probability of success (p) is constant for each trial. Here, n = 25 (number of trials) and p = 0.49 (probability of success).
Step 2: Use the binomial probability formula to calculate the probability of exactly 12 successes. The formula is: P(X = k) = (n choose k) * p^k * (1-p)^(n-k), where 'n choose k' is the binomial coefficient, p is the probability of success, and k is the number of successes. Here, k = 12.
Step 3: Calculate the binomial coefficient (n choose k), which is given by the formula: (n choose k) = n! / [k! * (n-k)!]. Substitute n = 25 and k = 12 into this formula.
Step 4: Substitute the values of p = 0.49, k = 12, and n = 25 into the binomial probability formula. Compute p^k (0.49^12) and (1-p)^(n-k) ((1-0.49)^(25-12)).
Step 5: Multiply the binomial coefficient from Step 3 by the probabilities calculated in Step 4 to find the final probability P(X = 12).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Binomial Distribution

The binomial distribution models the number of successes in a fixed number of independent Bernoulli trials, each with the same probability of success. In this context, each adult's opinion on climate change can be seen as a trial, where 'success' is defined as an adult believing that human activity contributes significantly to climate change. The distribution is characterized by two parameters: the number of trials (n) and the probability of success (p).
Video consigliato:
Percorso guidato
03:28
Mean & Standard Deviation of Binomial Distribution

Probability Mass Function (PMF)

The probability mass function gives the probability of obtaining exactly k successes in n trials for a binomial distribution. It is calculated using the formula P(X = k) = (n choose k) * p^k * (1-p)^(n-k), where 'n choose k' represents the binomial coefficient. This function is essential for determining the likelihood of observing a specific number of successes, such as exactly 12 adults in this scenario.
Video consigliato:
Percorso guidato
5:37
Introduction to Probability

Normal Approximation to the Binomial

For large sample sizes, the binomial distribution can be approximated by a normal distribution, which simplifies calculations. This approximation is valid when both np and n(1-p) are greater than 5. In this case, with n = 25 and p = 0.49, the normal approximation can be used to estimate probabilities, making it easier to analyze the distribution of opinions among the selected adults.
Video consigliato:
Percorso guidato
06:23
Using the Normal Distribution to Approximate Binomial Probabilities
Pratica correlata
Domanda del libro di testo

Use the probability distribution in Exercise 3 to find the probability of randomly selecting a game in which DeMar DeRozan had (a) fewer than four personal fouls,

68
views
Domanda del libro di testo

A survey of adults in the United States found that 61% ate at a restaurant at least once in the past week. You randomly select 30 adults and ask them whether they ate at a restaurant at least once in the past week. (Source: Gallup)


c. Is it unusual for exactly 14 out of 30 adults to have eaten in a restaurant at least once in the past week? Explain your reasoning.

69
views
Domanda del libro di testo

In Exercises 6–11, find the indicated area under the standard normal curve. If convenient, use technology to find the area.


Between z = 0 and z = 2.95

82
views
Domanda del libro di testo

Forty-nine percent of U.S. adults think that human activity such as burning fossil fuels contributes a great deal to climate change. You randomly select 25 U.S. adults. Find the probability that the number who think that human activity contributes a great deal to climate change is (b) between 8 and 11, inclusive,

72
views
Domanda del libro di testo

The life spans of car batteries are normally distributed, with a mean of 44 months and a standard deviation of 5 months.


c. What is the shortest life expectancy a car battery can have and still be in the top 5% of life expectancies?

96
views
Domanda del libro di testo

Use the probability distribution in Exercise 3 to find the probability of randomly selecting a game in which DeMar DeRozan had (c) between two and four personal fouls, inclusive.

89
views