PSYC 204 Lecture 12: PSYC STATS 12
Document Summary
Normal bell curve : total area probability = 1, asymptote tails = never, symmetrical in (+) & (-) infinity. Touch x-axis so (+) z & (-) z. Ex: check area of 0. 475 & which z-score correspond to = (+) / (-) 1. 96. * if sample iq - expect 95% of scores between 70 to 130 *remove tails of normal distribution. Real-world example: a factory produces bags of sugar. *what is probability of back < 1000g: convert to z-score, look up z-score in table. 0. 29 = area of 0. 11: answer = *half of curve = 0. 5 of all area. 0. 39 or 39% of bags will be < 1000g / 1kg. The accuracy requirements of consumer packaging & labeling act - regulations mandate that only. 2. 5% of all packages labeled as 1 kg can exceed (-) negative error larger than 10g. Sugar packaging machinery has standard deviation of 15g around its mean delivery.
