BSB123 Lecture Notes - Lecture 6: Central Limit Theorem, Standard Deviation, Statistical Parameter
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Statistical inference is the method for drawing conclusions about a population based on a sample taking into account sampling error. This unit focuses on two types of testing . A statistical method of determining the strength of evidence against the hypothesised value of a population parameter of interest. Using sample data to estimate the true value of a population parameter. Is the distribution of all the sample means that we can obtain from the population. Notes: the sample mean (xbar) is a random variable whereas mu is a fixed value, xbar (small letter) denoted a value of the random variable: xbar (capital letter). Suppose the population iq (x) is normally distributed, with mean (mu) 115 and standard deviation 6. The sample mean iq (xbar) is a rv. If the population is normal, the distribution of the sample mean (xbar) is always normal, regardless of sample size . Xbar will be approximately normal only if the sample size is large enough.