The normal curve Flashcards
Explain all the important parts of a normal curve
-Symmetrical bell shaped
- Used with continuous variables
-Peaks above a midway point
-mean, median, and mode are the same for the normal curve
In the normal curve, the standardized z-score has a mean of and a standard deviation of
A mean of zero
A standard deviation score of 1.
Every normal curve can be interpreted in exactly the same way once any distance from the mean is expressed in
standard deviation units
68% of the area under the normal curve is within one standard deviation above and below the mean
5% of the area under the normal curve is more than two standard deviations above and below the mean
Every normal curve can be interpreted in exactly the same way once any distance from the mean is expressed in standard deviation units
A unit free, standardized score
Indicates how many standard deviations a score is above or below the mean of a distribution
Z-scores
z = X - µ/
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z- score calculation
the original score
X
mean for the normal distribution of the original scores
µ
standard deviation for the normal distribution of the original scores
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Units of measurement cancel each other out – thus,
a unit free, standardized number
Z scores consist of two parts
- A positive or negative sign: Indicates whether the number is below or above the mean
- A number: Indicates the size of its deviation from the mean in standard deviation units
- A positive or negative sign: Indicates whether the number is below or above the mean
- A number: Indicates the size of its deviation from the mean in standard deviation units
z-scores