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28 Cards in this Set
- Front
- Back
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weighted mean
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mean of a group of means
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truncated
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use only part of the distribution
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median
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middle
skewed,truncated,open ended Q2 |
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open ended
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top or bottom category only has 1 limit
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mode
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most common score; crude measure
quick, easy, not unique, can have 2+ |
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mean
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most common, normal distributions
variance |
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skew relationships
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mean>median=>positive skew
mean <median=>negative skew mean=median=>no skew |
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dispersion
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spread or variability of scores around central tendency measure
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range
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hi score-lo score
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semi interquartile range (SIR) pr Q2
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use with median; median+-SIR cuts off middle 50% of scores
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variance or mean score
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s^2 or o^2
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standard deviation or root mean square
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s or o
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mean deviation method
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long but shows how scores vary from the mean
s^2= |
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raw score method
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easier less intuitive about mean
ss= |
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homogeneous sample
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data values similar=>low s^2 & s
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heterogeneous sample
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data values dissimilar => high s^2 & s
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kurtosis
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peaked or flat
s^4= |
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z score
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represents distance between score & mean relative to s
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standard normal distribution
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u=0 & o=1
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large values (distribution)
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low precision & high error
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small values (distribution)
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low error & high precision
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1 standard deviation
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68%
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2 standard deviation
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95%
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3 standard deviation
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99%
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mesokurtic
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3
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platykurtic
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<3
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leptokurtic
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>3
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skew/pearsons
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s^3=
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