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In Exercises 6.28 to 6.31, use StatKey or other technology to generate a bootstrap distribution of sample proportions and find the standard error for that distribution. Compare the result to the standard error given by the Central Limit Theorem, using the sample proportion as an estimate of the population proportion \(p\). Proportion of peanuts in mixed nuts, with \(n=100\) and \(\hat{p}=0.52\)

Short Answer

Expert verified
The standard error collected from the bootstrap distribution is compared with the calculated standard error from the Central Limit Theorem. The specific numerical answers will depend on the bootstrap distribution generated, which can vary.

Step by step solution

01

Calculate Standard Error using bootstrap distribution

To generate a bootstrap distribution of sample proportions, you take your sample data and repeatedly generate new samples by drawing from your original sample, calculating the sample proportion each time. This yields a distribution of sample proportions. The standard error of this bootstrap distribution can then be calculated as the standard deviation of this distribution.
02

Calculate Standard Error using CLT

The Central Limit Theorem (CLT) provides a method to calculate the standard error based on sample size \(n\) and sample proportion \(\hat{p}\). The standard error for the proportion is calculated using the formula \(\sqrt{\hat{p}(1-\hat{p})/n}\). In this exercise, with \(n=100\) and \(\hat{p}=0.52\), the standard error according to CLT would be \(\sqrt{0.52*(1-0.52)/100}\).
03

Comparison

Lastly, the calculated standard errors from the bootstrap distribution and the CLT are compared to each other. This comparison helps in understanding the practical utility of the Central Limit Theorem and assessing the accuracy of the result.

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Key Concepts

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

Sample Proportions
Understanding sample proportions is crucial when dealing with statistics, particularly in the context of bootstrap distributions. When we collect data, for instance, the proportion of peanuts in a mixed nuts sample, we're looking at a 'sample proportion' denoted as \(\hat{p}\). It's the fraction of the sample that exhibits the characteristic we're interested in, say, being peanuts in a bag of mixed nuts.

The concept becomes really handy when we want to make inferences about the population proportion, \(p\), which is the actual proportion we'd find if we could look at every single peanut and nut in the theoretical infinite 'population' of mixed nuts. Since we can only typically sample a fraction of the population, we use the sample proportion \(\hat{p}\) as an estimate for the true population proportion \(p\).

However, because we're sampling, there's a degree of uncertainty. To account for this, statisticians employ techniques like bootstrap distributions, which involve taking many samples from a single sample to simulate what different samples from the population might look like. This helps to understand the variability of sample proportions and provides a way to estimate standard errors and construct confidence intervals for the population proportion.
Standard Error
Now, let's delve into the standard error, a term that tells us how much a sample statistic, like the sample proportion, is expected to vary from one sample to another. To put it simply, if we were to take many samples, calculate the statistic for each one, and then measure how much those statistics spread out, we'd be talking about the standard error.

In the context of the problem at hand, after generating a bootstrap distribution, the standard error is nothing but the standard deviation of this distribution of sample proportions. It's a measure of how spread out these bootstrap sample proportions are. Getting this number is key because it tells us something about the precision of our sample proportion \(\hat{p}\) as an estimate for the population proportion \(p\).

It's worth noting that the smaller the standard error, the more precise our estimate is likely to be. This means we're more confident that our sample proportion is close to what the actual population proportion would be, assuming that the sample we're drawing from is representative of the population.
Central Limit Theorem
The Central Limit Theorem (CLT) is a statistical concept that plays a pivotal role in understanding the distribution of sample statistics. One of the key takeaways from the CLT is that no matter the original distribution of the population, the sampling distribution of the sample mean (or proportion) will tend to be normal or bell-shaped, provided the sample size is large enough.

This property is incredibly useful because it allows statisticians to make inferences about population parameters like the mean or proportion \(p\) even when the population distribution is unknown. According to the Central Limit Theorem, as the sample size increases, the distribution of the sample proportions becomes more and more normal and the standard error of the sampling distribution can be estimated with the formula \(\sqrt{\hat{p}(1-\hat{p})/n}\), where \(n\) is the sample size and \(\hat{p}\) is the sample proportion.

When applying the CLT, we use the sample proportion to gauge the true population proportion, which can be validated by comparing it against the bootstrap method. This theoretical underpinning of the CLT is essential for statisticians, especially when a direct computation through bootstrapping is impractical or when looking to affirm the accuracy of bootstrap results.

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Most popular questions from this chapter

In Exercises 6.150 and \(6.151,\) use StatKey or other technology to generate a bootstrap distribution of sample differences in proportions and find the standard error for that distribution. Compare the result to the value obtained using the formula for the standard error of a difference in proportions from this section. Sample A has a count of 30 successes with \(n=100\) and Sample \(\mathrm{B}\) has a count of 50 successes with \(n=250\).

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Who Eats More Fiber: Males or Females? Use technology and the NutritionStudy dataset to find a \(95 \%\) confidence interval for the difference in number of grams of fiber (Fiber) eaten in a day between males and females. Interpret the answer in context. Is "No difference" between males and females a plausible option for the population difference in mean number of grams of fiber eaten?

Physician's Health Study In the Physician's Health Study, introduced in Data 1.6 on page 37 , 22,071 male physicians participated in a study to determine whether taking a daily low-dose aspirin reduced the risk of heart attacks. The men were randomly assigned to two groups and the study was double-blind. After five years, 104 of the 11,037 men taking a daily low-dose aspirin had had a heart attack while 189 of the 11,034 men taking a placebo had had a heart attack. \({ }^{39}\) Does taking a daily lowdose aspirin reduce the risk of heart attacks? Conduct the test, and, in addition, explain why we can infer a causal relationship from the results.

\(\mathbf{6 . 2 2 0}\) Diet Cola and Calcium Exercise B.3 on page 349 introduces a study examining the effect of diet cola consumption on calcium levels in women. A sample of 16 healthy women aged 18 to 40 were randomly assigned to drink 24 ounces of either diet cola or water. Their urine was collected for three hours after ingestion of the beverage and calcium excretion (in \(\mathrm{mg}\) ) was measured. The summary statistics for diet cola are \(\bar{x}_{C}=56.0\) with \(s_{C}=4.93\) and \(n_{C}=8\) and the summary statistics for water are \(\bar{x}_{W}=49.1\) with \(s_{W}=3.64\) and \(n_{W}=8 .\) Figure 6.20 shows dotplots of the data values. Test whether there is evidence that diet cola leaches calcium out of the system, which would increase the amount of calcium in the urine for diet cola drinkers. In Exercise \(\mathrm{B} .3\), we used a randomization distribution to conduct this test. Use a t-distribution here, after first checking that the conditions are met and explaining your reasoning. The data are stored in ColaCalcium.

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