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22 Cards in this Set
 Front
 Back
Tail
definition 
The end of the distribution that has the fewest number of scores


Positively Skewed
definition 
When the scores cluster at the left end (0, origin) of the distribution


Negative Skewed
definition 
When the scores cluster at the right end of the distribution


Is there a way to get an idea of the amount of skewness? If so, how?

Yes.
Compare the median with the mean. 

Estimating amount of skewness
explanation 
Positive = mean LARGER than median
Negative = mean smaller than median 

Closer skewness is to zero...

The closer distribution is to being symmetical


Markedly Skewed
definition 
When a skewness value is greater than 1.0 or smaller than 1.0


Moderately (Slightly) Skewed
definition 
When a skewness is greater than zero, but less than 1


A distribution is Not normal if...

the ratio of skewness to standard error is greater than 2.0 or less than 2.0


Platykurtic
definition 
Large standard deviation with spread making graph spread out and flat


Leptokurtic
definition 
small standard deviations that leave graph with tall peaked curves


Mesokurtic
definition 
normal, bellshaped distribution


Kurtosis of mesokurtic is...

near zero


Kurtosis of playkurtic is...

values smaller than 1.0


Kurtosis of leptokurtic is...

values greater than +1.0


zcurve/zscore
alternate names 
1)Standard normal distribution
2)Standard score 

zscore
definition 
Converting a raw score from a normal distribttion to a score in a standardized normal distibution


zscore allows us to do 4 things...

1)determine exact proportion of scores fall between any 2 scores
2)how a score relates to other scores 3)compare scores 4) estimate probability of an event 

zscore
calculation 
(Raw score  Mean)
 Standard deviation 

If a score is Larger than the mean...

The zscore will be +


If a score is smaller than the mean...

the zscore will be negative


To determine the percentage of a score in relation to the whole, you should...

1)Calculate the zscore
2)Use a table to determine the percentage 3) Add 50.0 if you want the percentage under a score and Subtract from 50.0 to determine the percentage above the score 