/*! 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 34 Explain what a sampling distribu... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Explain what a sampling distribution is.

Short Answer

Expert verified
A sampling distribution is the distribution of a statistic (like the mean) calculated from multiple samples drawn from the same population.

Step by step solution

01

- Understanding the Population

A population is the entire set of individuals or items that are of interest. For example, if studying the average height of students in a school, the population would be all the students in that school.
02

- Defining a Sample

A sample is a subset of the population. It is drawn to make inferences about the population without measuring every single member. For instance, selecting 30 students from the school to measure their height.
03

- Collecting Multiple Samples

To understand the variability, multiple samples (each containing a subset of the population) are collected. Each sample will have its own set of data points.
04

- Calculating Sample Statistic

For each sample, a statistic (like the mean, median, or proportion) is calculated. For example, if measuring heights, calculate the mean height for each of the samples.
05

- Forming the Sampling Distribution

The sampling distribution is created by plotting all the calculated statistics from the different samples. This allows seeing how the sample statistic varies from sample to sample.
06

- Understanding Variability and Shape

The shape of the sampling distribution will often resemble a normal distribution, especially if the sample size is large, due to the Central Limit Theorem. The spread of this distribution gives insight into the variability of the sample statistics.

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Key Concepts

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

Population
In statistics, a population refers to the entire group of individuals or items that you are interested in studying. Imagine you want to know the average height of students in a particular school. Every single student in that school constitutes the population for your study. Understanding the population is crucial because it helps define the scope and applicability of your study results.

In many cases, studying the entire population is impractical, expensive, or time-consuming. That's why statisticians often rely on taking samples from the population.
Sample
A sample is a smaller subset selected from the entire population. By studying this smaller group, we can make estimates or inferences about the population as a whole. For example, instead of measuring the height of every student in the school, you might measure just 30 students.

Samples are particularly useful when the population is too large to study entirely. However, it's essential for the sample to be representative of the population to draw accurate conclusions. This is usually done using random sampling techniques.
Central Limit Theorem
The Central Limit Theorem (CLT) is a fundamental principle in statistics. It states that the sampling distribution of the sample mean will become approximately normal, or bell-shaped, if the sample size is large enough, regardless of the population's distribution. Here's why this is important:
  • It allows us to make probability statements about the sample mean.
  • It simplifies the analysis, making it easier to apply statistical methods.
  • It holds true even if the original population distribution is not normal.
Understanding the CLT is key to making accurate inferences from sample data.
Sample Statistic
A sample statistic is a numerical measure that describes some characteristic of a sample. Common sample statistics include the sample mean, median, and proportion.

For instance, if you measured the height of 30 students from our earlier example, the average height (mean) of these 30 students would be a sample statistic. Sample statistics are essential because they provide estimates about population parameters. Population parameters might be unknown or difficult to measure directly, so sample statistics are used to make educated guesses about them.
Variability
Variability refers to how spread out the data points are in a dataset. It is a measure of the dispersion or spread of the sample statistics. For instance, if you measure the heights of different samples of students, the variability will tell you how much these sample means differ from each other.

Understanding variability is crucial for grasping the reliability and precision of your inferences about the population. High variability indicates that the sample results are very spread out, while low variability suggests that the sample results are closely clustered around the population mean. This understanding helps in assessing the accuracy of our sample statistic estimates.

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Most popular questions from this chapter

Describe the sampling distribution of \(\hat{p}\). Assume that the size of the population is 25,000 for each problem. $$ n=1000, p=0.103 $$

Suppose you want to study the number of hours of sleep full-time college students at your college get each evening. To do so, you obtain a list of full-time students at your college, obtain a simple random sample of ten students, and ask each of them to disclose how many hours of sleep they obtained the most recent Monday. (a) What is the population of interest in this study? What is the sample? (b) Explain why number of hours of sleep in this study is a random variable. (c) After you obtain your ten observations, you compute the mean number of hours of sleep. Is this a statistic or a parameter? Why? (d) Is the mean number of hours computed in part (c) a random variable? Why? If it is a random variable, what is the source of variation? How does the source of variation in this study differ from that of Problem \(40 ?\)

Determine \(\mu_{\bar{x}}\) and \(\sigma_{\bar{x}}\) from the given parameters of the population and the sample size. \(\mu=27, \sigma=6, n=15\)

Marriage Obsolete? According to a study done by the Pew Research Center, \(39 \%\) of adult Americans believe that marriage is now obsolete. (a) Suppose a random sample of 500 adult Americans is asked whether marriage is obsolete. Describe the sampling distribution of \(\hat{p}\), the proportion of adult Americans who believe marriage is obsolete. (b) What is the probability that in a random sample of 500 adult Americans less than \(38 \%\) believe that marriage is obsolete? (c) What is the probability that in a random sample of 500 adult Americans between \(40 \%\) and \(45 \%\) believe that marriage is obsolete? (d) Would it be unusual for a random sample of 500 adult Americans to result in 210 or more who believe marriage is obsolete?

Afraid to Fly According to a study conducted by the Gallup organization, the proportion of Americans who are afraid to fly is \(0.10 .\) A random sample of 1100 Americans results in 121 indicating that they are afraid to fly. Explain why this is not necessarily evidence that the proportion of Americans who are afraid to fly has increased since the time of the Gallup study.

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