PSYCH 2220 Chapter Notes - Chapter 6: Unimodality, Standard Deviation, The Need
8 Feb 2018
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Ch 6 - the normal curve, standardization, and z scores. Normal curve - a specific bell-shaped curve that is unimodal, symmetric, and defined mathematically. As sample size increases (towards the population size), the distribution more and more closely resembles a normal curve. Standardization is a way to convert individual scores from diff normal distributions to a shared normal distribution w/ a known mean, standard deviation, and percentiles. A z score is the # of standard deviations a particular score is from the mean. A z score is part of its own distribution, the z distribution. Z scores let you make meaningful comparisons. You only need mean and standard deviation to compute a z score. The z distribution always has a mean of 0, and standard deviation of 1. Step 1) determine the distance of a particular person"s score (x) from the pop mean (mu) as part of the calculation: x - mu.
