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What is a point estimate, as used to introduce confidence intervals?
AAn interval of numbers guaranteed to contain the parameter
BThe known population standard deviation itself
CA single number computed from a sample to estimate a parameter
DThe margin of error attached to a confidence level
Answer & Solution
Correct answer: C. A single number computed from a sample to estimate a parameter
1. The glossary defines a point estimate directly.
2. It is a single number, computed from sample data, used to estimate an unknown population parameter.
3. The sample mean x-bar is a point estimate for μ, and the sample standard deviation s is a point estimate for σ.
4. Option A describes a confidence interval instead, which is a range rather than a single number, so it is a different concept.
_Source: OpenStax Introductory Statistics (CC BY 4.0), Ch 8 "Confidence Intervals", section 8.1 A Single Population Mean using the Normal Distribution_
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