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Norm Prob Dist
5.1
Question | Answer |
---|---|
What's a normal distribution? | a continuous probability distribution for random variable x. |
What's a normal curve? | a graph of norm dist. |
What's normal distribution property #1 | 1. mean, median, mode are equal. |
What's normal distribution property #2 | 2. normal curve is bell shaped and symmetric about the mean. |
What's normal distribution property #3 | 3. total area under normal curve equals 1. |
What's normal distribution property #4 | 4. normal curve approaches, but never touches, the x-axis as it extends further away from mean. |
What's normal distribution property #5 | 5. B/w u-o & u=o (in the center of the curve) graph curves upward to the left of u-o & to the right of u+o. |
what are inflection points | points at which curve changes from curving upward to curving downward |
what's the formula to find the z-score? | (x-u)/o |
What's a standard normal distribution? | normal distribution with mean of 0 and standard deviation of 1 |
what are the properties of a standard normal distribution? | (1).cumulative area (CA) is close to 0 for z-scores close to z=-3.49 (2) CA increases as z-scores increase (3) CA for z=0 is .5000 (4) CA is close to 1 for z-scores close to z=3.49 |
how do you find the area to left of z score | use stand norm table. |
dow do you find area to right of z score | b. 1 - (left of z, use table to find) |
how do you find area between 2 z-scores | find area to left of each z-score using table. Subtract high from low #. |
what's the area to LEFT of z=1.23? | Area to left=.8907 (coordinates: 1.2, .03) |
What's the area BETWEEN z=1.23 and z=-.75? | 1.23=.8907, -.75=2266, so area b/w=.8907-.2266=.6641 |
What's the area to RIGHT of z=1.23? | Area to right=1-.8907=.1093 |