mid 2 cheat sheet

mid 2 cheat sheet - Z-scores -Z-scores are standardized...

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Z-scores - Z-scores are standardized scores that tell where a raw scores (x) is located in an entire distribution in terms of standard deviation (SD) units. Purpose of z-scores Z-scores enable you to: -determine the relative standing of a raw score with a distribution -compare scores that come from different distributions -standardize a distribution to have a mean of 0 and a standard deviation of 1, or any mean and standard deviation you specify. -determine probability values associated with a range of raw scores Z-score formula Components of z-score -sign tells you if the score is above (z>0), or at (z=0) the mean. -magnitude tells you how far away the score is from the mean in standard deviation units. Converting z-score to raw score Z-score Transformations: Comparing score from different distribution -to compare scores, need to put them on a “common metric” -to do this, raw scores within each distribution are transformed to z-scores Transforming raw scores : designating your own μ and σ -convert raw score to z score using parameters from original distribution: -calculate new raw score, substituting in the new μ and σ. Transforming Raw scores to z-scores: transforming a set of raw scores to z-scores: -does not change the shape of the distribution -does not change the location of individual scores within the distribution Probability and the Normal distribution Random Sampling -each individual in a population must have an equal chance of being selected -we use sampling with replacement: each sample must be replaced before the next selection is made. Assumption of standard normal curve problems -the variable is normally distributed -the mean and standard deviation for the population is known. -the SNC does not apply if these two assumptions are not met Sampling Distribution of the Mean Samples and Sampling Error -with inferential statistics, we use sample statistics (e.g. M) to estimate population parameters (e.g. μ). -different samples from the same population will produce different
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mid 2 cheat sheet - Z-scores -Z-scores are standardized...

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