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Answer true or false. Explain your answer. For the same random sample, when the confidence level \(c\) is reduced, the confidence interval for \(\mu\) becomes shorter.

Short Answer

Expert verified
True. Lowering the confidence level decreases the confidence interval width.

Step by step solution

01

Recall the meaning of confidence level

The confidence level, denoted as \(c\), represents the probability that the confidence interval contains the true population mean \(\mu\). A higher confidence level means we are more confident that the interval captures \(\mu\).
02

Understand the relationship between confidence level and interval width

As the confidence level \(c\) increases, the range of values around the sample mean that we are confident includes \(\mu\) increases, leading to a wider confidence interval. Conversely, reducing \(c\) results in a narrower interval since we are less confident.
03

Apply this to the given scenario

The problem states that if you reduce \(c\), the confidence interval becomes shorter. Based on Step 2, this statement is correct. Lowering the confidence level means the interval does not need to be as wide to encompass the true mean with that level of certainty.

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Key Concepts

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

Confidence Level
Confidence level is a key term in statistics when constructing confidence intervals. It is expressed as a percentage, reflecting how sure we are that the true population mean falls within the estimated range. A higher confidence level implies we are more certain of our estimation, often leading to a wider interval.
For instance, a confidence level of 95% suggests that if we were to take 100 different samples and compute a confidence interval for each, about 95 of them would contain the true population mean. This demonstrates how a confidence level is about the level of assurance in our statistical claims, impacting how much risk we accept when making inferences.
Understanding the confidence level helps gauge the reliability of conclusion drawn from sample data. Thus, choosing an appropriate confidence level balances the interval width and certainty in analysis.
Population Mean
The population mean, often represented as \( \mu \), is the average value within a complete population. In many statistical scenarios, we aim to estimate this mean using sample data because collecting data from an entire population can be impractical.
When constructing a confidence interval, the sample mean is used as a point estimate for the population mean. However, the sample is just a part of the whole, so our estimate comes with uncertainty.
Through confidence intervals, we incorporate a range that likely includes the population mean, indicating the potential variation in our estimation. Accurately estimating the population mean is central to making credible statistical inferences and crafting actionable insights, based on sample data.
Statistical Significance
Statistical significance helps us identify whether the sample data provides enough evidence to make conclusions about the broader population. It often relates to the idea of hypothesis testing but is also vital when interpreting confidence intervals.
In the context of confidence intervals, a narrow interval at a high confidence level makes our estimate of the population mean more statistically significant. This indicates that fewer external factors and random variations influence our result.
Conversely, a wider interval, although providing a higher level of coverage, may suggest less precision in our predictions, potentially affecting their statistical significance. Understanding statistical significance helps assess the meaningfulness of data analysis and whether observed patterns may be due to chance.
Interval Width
Interval width is influenced by how confident we want to be about our estimation. The confidence interval's width tells us about the precision and reliability of our estimation.
A narrower interval implies more precision in estimating the population mean, but it may come with lower confidence, implying higher risk. Conversely, a wider interval heightens the certainty that we capture the true mean, yet with reduced precision.
Deciding on the interval width requires a balance between precision and confidence. Statisticians often choose an interval width based on the context of their study, weighing how much risk or precision is suitable for their conclusion. Understanding interval width allows us to critically evaluate the trade-offs inherent in statistical analysis and reporting.

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