MATH 2321 Midterm: Stats Exam 2
2 Apr 2016
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Document Summary
Normal distribution: bell curve, with scores in their natural/ original units. Standardized normal distribution: bell curve, scores in standardized units (z-scores), always has a mean 0, sd=1. Bell shape, most area under curve falls in middle, tails of distribution approach the x- axis but never touch. Can be narrow or wide, depending on standard deviation. All are bilateral symmetry, half scores fall on either side of mean. Assume we have a large n (>25) and a normal distribution we can assume: majority of scores will fall within one st dev of mean, minority of scores fall more than two standard deviations away. Unit free standardized scores that indicates how many standard deviations a score is above or below the mean. Use when data is interval or ratio and symmetric and normal. A correlation can be thought of as a descriptive statistic for the relationship between two variables. The correlation coefficient may take on any value between plus and minus one.
