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A.9 ci for a mean


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A.9 ci for a mean

  1. 1. Confidence Interval for a Mean
  2. 2. Confidence Interval for a mean (x) Estimation Requirements: 1. Simple Random Sampling 2. Sampling distributed is approximately normally distributed How to find a CI for a Mean (method same as described before) 1. sample statistic (use sample proportion to estimate population proportion) 2. CL (90%, 95%, 99%) 3. ME= CV x SD or ME= CV x SE 4. Specify CI: sample statistic + ME written as: (Sample Stat – ME, Sample Stat + ME)
  3. 3. Variability of Sample Mean • Must compute SE of sampling distribution • When the population is at least 10 times bigger than the sample size, we can approximate the SE: ** this is found on the table under single-sample mean When you do not have the population SD (which is usually the case) must use a t-score.