Re: Confidence Interval - Definition of Confidence Interval
Thanks Harry and Steve, actually these 2 days, I was referring back to the Statistics Inference material in my last master degree stated that:
The probability that random interval covers the unknown true mean is 0.95 (if 95% confidence interval was chosen). If the samples of size n were repeatedly drawn from the normal population and the random interval were computed for each sample, then the relative frequency of those intervals containing the true unknown mean would approach 95%.
From here I understand that, if the population is in normal distribution, the 95% of the confidence interval will always cover the unknown true mean. (this is support by the 68, 95 and 99.7 rules). If the population is not in the normal distribution, based on the Central Limit Theorem, each sample was drawn with large sample size will be in the normal distribution. With this, the true mean of the population may not be covered in the 95% of the confidence interval.
failing to plan is planning to fail ~ Joseph Juran