APST 207 Lecture Notes - Lecture 8: Confidence Interval, Standard Deviation, Simple Random Sample
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Based on how confident we want to be that our sample really does come from a different population. We stick to 95% and 99% confidence (normally) For example, at a 95% confidence level we"re saying we are 95% confident that our sample mean comes from a population with a different mean and standard deviation. Any absolute score higher than 1. 6 is considered extreme. Any p-value lower than . 025 is considered extreme when looking at one tail, when looking at both tails it"s . 05. Zscore: absolute z-score> 2. 57 higher than 2. 58 is considered extreme. Any p value lower than . 005 is considered extreme when look at one tail, when looking at both tails it"s . 01. The range in which our population mean ( ) is likely to fall is called the confidence interval ci. To calculate the ci we need three things: The standard error of the mean for our sample. The z-score associated with how confident we want to be.
