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Ch. 7 - Hypothesis Testing with One Sample
Larson - Elementary Statistics: Picturing the World 8th Edition
Larson8th EditionElementary Statistics: Picturing the WorldISBN: 9780137493470당신이 사용하는 게 아니라요?교과서 변경
7장, 문제 7.2.31

In Exercises 29–32, test the claim about the population mean at the level of significance α. Assume the population is normally distributed.


Claim: ; μ ≠ 5880; α = 0.03; α = 413
Sample statistics: x_bar = 5771, n = 67

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Step 1: Identify the null hypothesis (H₀) and the alternative hypothesis (Hₐ). The null hypothesis is H₀: μ = 5880, and the alternative hypothesis is Hₐ: μ ≠ 5880. This is a two-tailed test because the claim specifies 'not equal to' (≠).
Step 2: Calculate the test statistic using the formula for a t-test: t = (x̄ - μ) / (s / √n), where x̄ is the sample mean, μ is the population mean under the null hypothesis, s is the sample standard deviation, and n is the sample size. Substitute the given values: x̄ = 5771, μ = 5880, s = 413, and n = 67.
Step 3: Determine the degrees of freedom (df) for the t-distribution. For a single-sample t-test, df = n - 1. In this case, df = 67 - 1 = 66.
Step 4: Find the critical t-value(s) for a two-tailed test at the significance level α = 0.03 and df = 66. Use a t-distribution table or statistical software to find the critical values. These values will define the rejection region for the null hypothesis.
Step 5: Compare the calculated t-value from Step 2 to the critical t-values from Step 4. If the calculated t-value falls in the rejection region (i.e., beyond the critical values), reject the null hypothesis. Otherwise, fail to reject the null hypothesis. Interpret the result in the context of the claim.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Hypothesis Testing

Hypothesis testing is a statistical method used to make decisions about a population based on sample data. It involves formulating a null hypothesis (H0) and an alternative hypothesis (H1), then using sample statistics to determine whether to reject H0 in favor of H1. In this case, the null hypothesis would state that the population mean μ equals 5880, while the alternative hypothesis claims that μ does not equal 5880.
추천 영상:
가이드 코스
06:21
Step 1: Write Hypotheses

Level of Significance (α)

The level of significance, denoted as α, is the probability of rejecting the null hypothesis when it is actually true, also known as a Type I error. In this scenario, α is set at 0.03, indicating a 3% risk of concluding that a difference exists when there is none. This threshold helps determine the critical value for the test statistic, which is essential for making a decision regarding the null hypothesis.
추천 영상:
가이드 코스
04:46
Step 4: State Conclusion Example 4

Sample Mean and Standard Error

The sample mean (x̄) is the average value of a sample, which in this case is 5771. The standard error (SE) measures the dispersion of the sample mean from the population mean and is calculated using the sample standard deviation divided by the square root of the sample size (n). Understanding the sample mean and standard error is crucial for calculating the test statistic and determining whether the sample provides enough evidence to reject the null hypothesis.
추천 영상:
가이드 코스
05:11
Sampling Distribution of Sample Proportion
관련 실천
교과서 질문

In Exercises 3–6, determine whether a normal sampling distribution can be used. If it can be used, test the claim.

Claim: p > 0.70, α=0.04. Sample statistics: p_hat = 0.64, n=225

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교과서 질문

Hypothesis Testing Using Rejection Regions In Exercises 23–30, (a) identify the claim and state H0 and Ha, (b) find the critical value(s) and identify the rejection region(s), (c) find the standardized test statistic X^2, (d) decide whether to reject or fail to reject the null hypothesis, and (e) interpret the decision in the context of the original claim. Assume the population is normally distributed.


Salaries The annual salaries (in dollars) of 15 randomly chosen senior level graphic design specialists are shown in the table at the left. At α=0.05, is there enough evidence to support the claim that the standard deviation of the annual salaries is different from \$13,056?


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교과서 질문

In Exercises 29–32, test the claim about the population mean at the level of significance α. Assume the population is normally distributed.


Claim: ; μ ≤ 22,500; α = 0.01; α = 1200

Sample statistics: x_bar = 23,500, n = 45

103
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교과서 질문

In Exercises 15–22, test the claim about the population variance or standard deviation at the level of significance Assume the population is normally distributed.

Claim: σ<40, α=0.01 . Sample statistics: s=40.8, n=12

86
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교과서 질문

Explain how to test a population variance or a population standard deviation.

123
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교과서 질문

In Exercises 7–12, find the critical value(s) and rejection region(s) for the type of chi-square test with sample size n and level of significance α.


Left-tailed test, n=24,α=0.05

89
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