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Course: Statistics and probability?>?Unit 11
Lesson 2: Estimating a population proportion- Confidence interval example
- Margin of error 1
- Margin of error 2
- Conditions for valid confidence intervals for a proportion
- Conditions for confidence interval for a proportion worked examples
- Reference: Conditions for inference on a proportion
- Conditions for a z interval for a proportion
- Critical value (z*) for a given confidence level
- Finding the critical value z* for a desired confidence level
- Example constructing and interpreting a confidence interval for p
- Calculating a z interval for a proportion
- Interpreting a z interval for a proportion
- Determining sample size based on confidence and margin of error
- Sample size and margin of error in a z interval for p
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Sample size and margin of error in a z interval for p
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Problem
Jonah wants to make a one-sample interval using confidence to estimate what proportion of silicon wafers at his factory are defective. He wants the margin of error to be no more than . A previous study suggests that about of these wafers are defective.
If we assume , what is the smallest sample size required to obtain the desired margin of error?