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Water samples are taken from water used for cooling as it is being discharged from a power plant into a river. It has been determined that as long as the mean temperature of the discharged water is at most \(150^{\circ} \mathrm{F}\), there will be no negative effects on the river's ecosystem. To investigate whether the plant is in compliance with regulations that prohibit a mean discharge water temperature above \(150^{\circ}, 50\) water samples will be taken at randomly selected times and the temperature of each sample recorded. The resulting data will be used to test the hypotheses \(H_{0}: \mu=150^{\circ}\) versus \(H_{\mathrm{a}}: \mu>150^{\circ}\). In the context of this situation, describe type I and type II errors. Which type of error would you consider more serious? Explain.

Short Answer

Expert verified
Type II error is more serious, as it could lead to environmental harm.

Step by step solution

01

Understanding the Hypotheses

We are given the null hypothesis, \(H_0: \mu = 150^\circ\), which represents that the mean temperature of discharged water is compliant with regulations. The alternative hypothesis, \(H_a: \mu > 150^\circ\), suggests non-compliance, indicating the mean discharge temperature is higher than allowed.
02

Defining Type I Error

A Type I error occurs when we reject the null hypothesis, \(H_0: \mu = 150^\circ\), when it is actually true. In this context, it would mean concluding that the mean temperature exceeds \(150^\circ\) when, in reality, it does not.
03

Defining Type II Error

A Type II error happens when we fail to reject the null hypothesis when the alternative hypothesis is true. Here, it would mean concluding that the mean temperature does not exceed \(150^\circ\) when, in fact, it does.
04

Comparing Error Severity

A Type I error might lead to unnecessary regulatory actions against the plant, even though it is in compliance. A Type II error could result in continued environmental harm due to unacknowledged regulatory non-compliance. Typically, a Type II error is considered more serious here, as it has the potential to cause harm to the river ecosystem.

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Key Concepts

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

Type I Error
In hypothesis testing, a Type I error happens when we mistakenly reject a true null hypothesis. It's important to picture this in our scenario: imagine you're drawing a wrong conclusion about the power plant's compliance based on sample data. You end up believing the plant is discharging water at temperatures above 150°F, even though everything is within acceptable limits. This error is like sounding a false alarm. Why? Because you're triggering regulatory alerts and possibly causing the plant to take unnecessary steps to adjust their procedures. A Type I error in our situation could lead to:
  • Unjustified regulatory action against the plant.
  • Wasted resources on unnecessary adjustments.
  • Potential legal and financial impacts on the power plant.
These actions all come from the incorrect assumption that the power plant is non-compliant, even though they are actually following the rules.
Type II Error
When discussing errors in hypothesis testing, a Type II error occurs when the alternative hypothesis is true, but we fail to reject the null hypothesis. In simpler terms, it means we conclude the power plant is compliant when, in fact, the discharge temperature is above 150°F. This is where dangerous forms of complacency come in. Here, a Type II error might cause:
  • Undetected environmental damage as regulatory breaches go unnoticed.
  • Sustained harm to the river ecosystem due to higher water temperatures.
  • Loss of biodiversity and long-term damage to aquatic life.
The severity of this error comes from continued non-compliance, which means ongoing harm. Therefore, this error is seen as more significant in our context than a Type I error because it misleads us into thinking everything is fine when it really isn't.
Environmental Compliance
Environmental compliance ensures that activities such as those in a power plant respect environmental laws and regulations. In this exercise, it pertains directly to monitoring water temperature discharged from a power plant to safeguard the river's ecosystem. Keeping the temperature at or below 150°F is crucial for maintaining a healthy and balanced river environment. When regulating environmental compliance:
  • Temperature limits are set to protect aquatic life and river conditions.
  • Regular sampling checks ensure compliance to prevent excessive thermal pollution.
  • Actions like hypothesis testing are used to detect infractions and implement changes if needed.
Compliance is a preventative measure designed to minimize or eliminate environmental harm before damage occurs. Failure to comply can have serious consequences not only for the environment but also for the entities responsible for discharging into natural ecosystems. Thus, effective monitoring and analysis, like the temperature tests discussed, are crucial for upholding environmental standards.

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Most popular questions from this chapter

For a fixed alternative value \(\mu^{\prime}\), show that \(\beta\left(\mu^{\prime}\right) \rightarrow 0\) as \(n \rightarrow \infty\) for either a one-tailed or a two-tailed \(z\) test in the case of a normal population distribution with known \(\sigma\).

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