Use the Normal Curve Areas: % of Normal Curve between the Mean and the Z scores Shown and % of Scores in the Tail for the Z scores shown in Table A-1 Appendix: Tables in Statistics Psychology Book: 978-0-205-25814-4 h. The mean for quiz #1 was 1.14, the standard deviation for the quiz was .30 i. What proportion of class scored above 1.14? ii. What proportion of the class scored below .8? iii. What proportion of the class scored between a 1.0 and a 1.5? iv. What quiz grades marked off where the middle 95% of the class scored? Show all work and draw the bell shape curves reflecting each
Continuous Probability Distributions
Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.
Normal Distribution
Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!
Use the Normal Curve Areas: % of Normal Curve between the Mean and the Z scores Shown and % of Scores in the Tail for the Z scores shown in Table A-1 Appendix: Tables in Statistics Psychology Book: 978-0-205-25814-4
h. The mean for quiz #1 was 1.14, the standard deviation for the quiz was .30
i. What proportion of class scored above 1.14?
ii. What proportion of the class scored below .8?
iii. What proportion of the class scored between a 1.0 and a 1.5?
iv. What quiz grades marked off where the middle 95% of the class scored?
Show all work and draw the bell shape curves reflecting each
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