Exam 3 review - Discussion Section 227 11/30/10 Exam 3...

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11/30/10 Exam 3 Review – Selected Topics Point estimates vs. interval estimates Estimates of population parameters can be either point estimates or interval estimates. A point estimate (e.g. sample mean) is precise but likely inaccurate An interval estimate is less precise but likely more accurate. It is a range of sample statistics we could expect to have if we repeatedly conducted hypothesis tests using samples from our population. Confidence interval : an interval estimate based on our sample mean that includes the population mean a certain percentage of the time (e.g. 95%) if we were to sample from the same population repeatedly. Example 1: Calculating confidence intervals in a Z distribution μ = 72, σ = 10, M = 75, n = 40; we want to calculate a 95% confidence interval around this mean. 1. Draw a sampling distribution and put the sample mean in the middle. Write the percentage area under the curve. 2. Use the unit normal table to find the Z values marking the upper and lower boundaries of the
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This note was uploaded on 02/21/2012 for the course PYSC 227 taught by Professor Fairchild during the Fall '10 term at South Carolina.

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Exam 3 review - Discussion Section 227 11/30/10 Exam 3...

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