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SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

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IGRAPH 765<br />

Number of Cases Less Than or Equal to (NLE(x)). The number of cases below or equal to the<br />

specified value.<br />

Percentage of Cases Above (PGT(x)). The percentage of cases having values above the specified<br />

value.<br />

Percentage of Cases Between (PIN(x1,x2)). The percentage of cases between two specified<br />

values.<br />

Percentage of Cases Equal to (PEQ(x)). The percentage of cases equal to the specified value.<br />

Percentage of Cases Greater Than or Equal to (PGE(x)). The percentage of cases having values<br />

above or equal to the specified value.<br />

Percentage of Cases Less Than (PLT(x)). The percentage of cases having values below the<br />

specified value.<br />

Percentage of Cases Less Than or Equal to (PLE(x)). The percentage of cases having values<br />

below or equal to the specified value.<br />

Percentiles (PTILE(x)). The data value below which the specified percentage of values fall<br />

within each category.<br />

Skewness (SKEW). A measure of the asymmetry of a distribution. The normal distribution<br />

is symmetric and has a skewness value of 0. A distribution with a significant positive<br />

skewness has a long right tail. A distribution with a significant negative skewness has a<br />

long left tail.<br />

Standard Deviations (STDDEV). A measure of dispersion around the mean, expressed in the<br />

same units of measurement as the observations, equal to the square root of the variance. In<br />

a normal distribution, 68% of cases fall within one SD of the mean and 95% of cases fall<br />

within two SD’s.<br />

Standard Errors of Kurtosis (SEKURT). The ratio of kurtosis to its standard error can be used<br />

as a test of normality (that is, you can reject normality if the ratio is less than –2 or greater<br />

than +2). A large positive value for kurtosis indicates that the tails of the distribution are<br />

longer than those of a normal distribution; a negative value for kurtosis indicates shorter<br />

tails (becoming like those of a box-shaped uniform distribution).<br />

Standard Errors of the Mean (SEMEAN). A measure of how much the value of the mean may<br />

vary from sample to sample taken from the same distribution. It can be used to roughly<br />

compare the observed mean to a hypothesized value (that is, you can conclude the two<br />

values are different if the ratio of the difference to the standard error is less than –2 or greater<br />

than +2).<br />

Standard Errors of Skewness (SESKEW). The ratio of skewness to its standard error can be<br />

used as a test of normality (that is, you can reject normality if the ratio is less than –2 or<br />

greater than +2). A large positive value for skewness indicates a long right tail; an extreme<br />

negative value, a long left tail.<br />

Sums (SUM). The sums of the values within each category.<br />

Sums of Absolute Values (SUMAV). The sums of the absolute values within each category.<br />

Sums of Squares (SUMSQ). The sums of the squares of the values within each category.

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