STATS 2B03 Lecture Notes - Central Limit Theorem, Histogram, Standard Deviation
19 Jun 2013
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Histogram (normal variance) of a population that is normal with mean and variance 2. Histogram of population that is not normally distributed, with mean and variance 2, sample of size n from this population: x1avg, x2avg, x3avg, xkavg. Most samples will have an average close to 40. Symmetric distribution, but is not as spread out. Histogram of xavg will be approximately normally distributed with mean. Example: the average cholesterol level for women aged 20-29 is 183, with standard deviation 37. In a sample of 40 women aged 20-29, find the probability that the average cholesterol level is greater than 195. Xavg is approximately normal with xavg= =183 and xavg= Probability for an average as oppose to picking one random variable. Example: iqs are normally distributed with mean 100 and standard deviation: find the probability that a randomly selected person has an iq less than.
