# Week 4 Discussion - Confidence Interval

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Point Estimate vs. Interval Estimate

To estimate population parameters, statisticians use sample statistics. For example, we use sample means to estimate population means and we use sample proportions to estimate population proportions. An estimate of a population parameter can be expressed in one of two ways: * Point estimate. A point estimate of a population parameter is a single value of a statistic. For example, the sample mean x is a point estimate of the population mean μ. In the same way, a sample proportion p is a point estimate of the population proportion P. * Interval estimate. An interval estimate is defined by two numbers, and the population parameter is said to lie between those two numbers. For example, a < x < b represents an interval estimate of the population mean μ. It expresses that the population mean is greater than a but less than b. Confidence Intervals

To express the precision and uncertainty that are associated with a particular sampling method statisticians use a confidence interval. A confidence interval consists of three parts: * A confidence level.

* A statistic.

* A margin of error.

The confidence level is used to describe the uncertainty of a sampling...

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