MAS 201 Lecture Notes - Lecture 7: Sample Size Determination, Confidence Interval
11 Apr 2017
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Confidence interval for the mean (when standard deviation is known: 95% confidence interval for the mean a. i. An estimate of the mean, so that, if one selected 100 samples of size n from the population, 95 out of the 100 intervals constructed will contain the population mean, and 5 will not contain the population mean a. ii. There is no way to know whether the confidence interval one constructs contains the mean or not a. iii. If one would like to increase the level of confidence, say to 99%, then the value of z would change. Confidence interval for mean (when standard deviation unknown: the previous confidence interval for the mean was when standard deviation was known. What happens if it"s unknown: estimate the population standard deviation with s (the sample standard deviation) b. i. This increases the uncertainty; therefore, the distribution needs to take this into consideration b. ii.
