POLSCI 3NN3 Lecture 5: LEC 5 - JAN 19 - MEASURES OF DISPURSION + weekly study guide
28 Jan 2017
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Measures of central tendency gives us 3 values that are representative of the scores relative to a. Measures of dispersion (4a) particular value: mode, median, mean, can always report all three. If using just one there are considerations to be had: nominal can only use mode. Outliers impact measures of central tendency and shift it away from where most of the scores are. Three different shapes that we will focus on. An unscrewed, symmetrical distribution (the mean and median are equal) A positively skewed distribution (the mean is greater in value than the median) A negatively skewed distribution (the mean is less than the median) With positive and negative skewed distribution think about whether mean or median are best to describe what is happening. Measures of central tendency like the mean, median and mode only tell us part of the descriptive story: besides center it is important to know the variety of scores.
