SCI1020 Lecture 6: Part 3a Towards inference
22 Dec 2018
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Random variable: individual outcomes are uncertain but there is a regular distribution o number of repetitions. Chance behaviour is unpredictable in the short run but has a regular and predictable pa tossing a coin!) Probability is the science of chance behaviour; we can use probability to gain useful resu samples and randomized comparative experiments. The law of large numbers: as the number of (independent) observations sampled incre gets closer and closer to the true value in the population. Probabilities can be assigned to intervals of outcomes. Standardized scores, z-score = position of individual result relative to the whole popula. A numerical value associated with a population is called a parameter : (fixed) population mean: symbol (mu) population standard deviation: (sigma) population proportion: symbol: p. A numerical value computed from a sample estimates the parameter above and is calle sample mean: symbol (x-bar) sample standard deviation: symbol is s sample proportion: symbol is (p-hat)
