/*! 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 105 To create a confidence interval ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

To create a confidence interval from a bootstrap distribution using percentiles, we keep the middle values and chop off some number of the lowest values and the highest values. If our bootstrap distribution contains values for 1000 bootstrap samples, indicate how many we chop off at each end for each confidence level given. (a) \(95 \%\) (b) \(90 \%\) (c) \(98 \%\) (d) \(99 \%\)

Short Answer

Expert verified
(a) Chop off 25 values at each end for a 95% confidence interval. (b) Chop off 50 values at each end for a 90% confidence interval. (c) Chop off 10 values at each end for a 98% confidence interval. (d) Chop off 5 values at each end for a 99% confidence interval.

Step by step solution

01

Understanding bootstrap distribution and confidence intervals

A bootstrap distribution is a sample distribution of a statistic (like the mean) from a large number of resamples from a sample data set. Confidence intervals are calculated ranges within which the true population parameter value lies with a certain degree of confidence. In this case, for a given confidence level, x percent, we chop off (100 - x)/2 percent of the values at each end of the bootstrap distribution.
02

Chop off values for 95% confidence interval

For a 95% confidence interval, we chop off (100 - 95)/2 = 2.5% of values at each end of the bootstrap distribution. Since our bootstrap distribution contains 1000 bootstrap samples, we chop off 0.025 * 1000 = 25 values at each end.
03

Chop off values for 90% confidence interval

For a 90% confidence interval, we chop off (100 - 90)/2 = 5% of values at each end of the bootstrap distribution. So, we chop off 0.05 * 1000 = 50 values at each end.
04

Chop off values for 98% confidence interval

For a 98% confidence interval, we chop off (100 - 98)/2 = 1% of values at each end of the bootstrap distribution. So, we chop off 0.01 * 1000 = 10 values at each end.
05

Chop off values for 99% confidence interval

For a 99% confidence interval, we chop off (100 - 99)/2 = 0.5% of values at each end of the bootstrap distribution. So, we chop off 0.005 * 1000 = 5 values at each end.

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 91Ó°ÊÓ!

Key Concepts

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

Bootstrap Distribution
The bootstrap distribution is a powerful statistical tool used to estimate the sampling distribution of a statistic, such as the mean or median, from a single sample. This technique involves repeatedly resampling the original dataset with replacement to create many simulated samples, known as bootstrap samples.

These simulations generate a myriad of statistic values which form the bootstrap distribution. By analyzing this distribution, we can gain insight into the variability and possible values of the statistic in the larger population. The bootstrap distribution is particularly useful when the actual distribution of the data is unknown or when the sample size is too small for standard statistical methods to be reliable.

In educational terms, imagine you have only one bag of assorted candies to estimate the percentage of each flavor in the entire candy population. By repeatedly taking handfuls out of the bag, then putting them back and taking another handful, you start to build a picture of what the whole population might look like. Similarly, bootstrap distribution provides a model to understand the whole population from a single sample.
Percentile-Based Confidence Interval
A percentile-based confidence interval uses percentiles of the bootstrap distribution to set the bounds for the interval where the true population parameter is believed to lie with a specified level of confidence, such as 95% or 99%.

This method uses the idea that certain percentages of the bootstrap distribution fall below and above the true parameter. For example, in a 95% confidence interval, the goal is to find two points on the distribution where 2.5% of the values fall below the lower bound and 2.5% above the upper bound, leaving 95% of values in between.

Using percentile-based intervals is like cutting off the ends of a rope so that the length in-between covers a specific portion of the total length. If that rope represents all possible outcomes based on resampling, the middle part is your confidence interval where the true average length is likely to be found. This approach offers a simple, non-parametric way to estimate intervals when data doesn't necessarily follow a normal distribution or when theoretical distributions are difficult to apply.
Resampling Statistics
Resampling statistics is a branch of statistics that involves drawing repeated samples from observed data with the aim of estimating a population characteristic. This non-parametric approach doesn't rely on assumptions about the data distribution and is embodied by techniques such as bootstrapping and the permutation test.

The essence of resampling is to use the actual data to generate new samples that could represent possible outcomes were the study or experiment repeated. It's like shuffling a deck of cards several times to see the different possible sequences - each shuffle gives a potential outcome of the cards. Similarly, resampling allows statisticians to draw conclusions about the population from which the original sample was taken.

In the context of educational exercises, it's crucial for learners to understand that resampling provides a method to assess the reliability of sample statistics without relying heavily on large samples or normal distribution assumptions. It essentially enables students to make more robust inferences based on the data at hand.

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

What Is an Average Budget for a Hollywood Movie? Data 2.7 on page 95 introduces the dataset HollywoodMovies, which contains information on more than 900 movies that came out of Hollywood between 2007 and \(2013 .\) We will consider this the population of all movies produced in Hollywood during this time period. (a) Find the mean and standard deviation for the budgets (in millions of dollars) of all Hollywood movies between 2007 and \(2013 .\) Use the correct notation with your answer. (b) Use StatKey or other technology to generate a sampling distribution for the sample mean of budgets of Hollywood movies during this period using a sample size of \(n=20\). Give the shape and center of the sampling distribution and give the standard error.

Proportion of registered voters in a county who voted in the last election, using data from the county voting records.

Adolescent Brains Are Different Researchers continue to find evidence that brains of adolescents behave quite differently than either brains of adults or brains of children. In particular, adolescents seem to hold on more strongly to fear associations than either children or adults, suggesting that frightening connections made during the teen years are particularly hard to unlearn. In one study, \({ }^{25}\) participants first learned to associate fear with a particular sound. In the second part of the study, participants heard the sound without the fear-causing mechanism, and their ability to "unlearn" the connection was measured. A physiological measure of fear was used, and larger numbers indicate less fear. We are estimating the difference in mean response between adults and teenagers. The mean response for adults in the study was 0.225 and the mean response for teenagers in the study was \(0.059 .\) We are told that the standard error of the estimate is 0.091 . (a) Give notation for the quantity being estimated. (b) Give notation for the quantity that gives the best estimate, and give its value. (c) Give a \(95 \%\) confidence interval for the quantity being estimated. (d) Is this an experiment or an observational study?

SKILL BUILDER 1 In Exercises 3.41 to \(3.44,\) data from a sample is being used to estimate something about a population. In each case: (a) Give notation for the quantity that is being estimated. (b) Give notation for the quantity that gives the best estimate. A random sample of registered voters in the US is used to estimate the proportion of all US registered voters who voted in the last election.

Headaches and Handedness A study was conducted to investigate the relationship between severe headaches and being left- or right-handed. 48 (Incidentally, Lisa Kudrow, who played Phoebe Buffay on the hit sitcom "Friends," is an author on this study.) Of 273 participants with cluster headaches, 24 were left-handed. Of 477 participants with migraine headaches, 42 were left-handed. (a) Give an estimate for the proportion of cluster headache sufferers who are left-handed. (b) Use StatKey or other technology to construct and interpret a \(95 \%\) confidence interval for the proportion of cluster headache sufferers who are left-handed. (c) Give an estimate for the proportion of migraine sufferers who are left- handed. (d) Use StatKey or other technology to construct and interpret a \(95 \%\) confidence interval for the proportion of migraine sufferers who are lefthanded. (e) Compare your confidence intervals in parts (b) and (d). Which is more narrow? Explain why.

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.