SPSS® 12.0 Command Syntax Reference

Example
FREQUENCIES 603
FREQUENCIES VARIABLES=TEMP
/GROUPED=TEMP (0.5)
/NTILES=10.
• The values of TEMP (temperature) in this example were recorded using an inexpensive
thermometer whose readings are precise only to the nearest half degree.
• The observed values of 97.5, 98, 98.5, 99, and so on, are treated as group midpoints,
smoothing out the discrete distribution. This yields more accurate estimates of the deciles.
Example
FREQUENCIES VARIABLES=AGE
/GROUPED=AGE (17.5, 22.5, 27.5, 32.5, 37.5, 42.5, 47.5
52.5, 57.5, 62.5, 67.5, 72.5, 77.5, 82.5)
/PERCENTILES=5, 10, 25, 50, 75, 90, 95.
• The values of AGE in this example have been estimated to the nearest five years. The first
category is 17.5 to 22.5, the second is 22.5 to 27.5, and so forth. The artificial clustering
of age estimates at multiples of five years is smoothed out by treating AGE as grouped
data.
• It is not necessary to recode the ages to category midpoints, since the interval boundaries
are explicitly given.
PERCENTILES Subcommand
PERCENTILES displays the value below which the specified percentage of cases falls. The
desired percentiles must be explicitly requested. There are no defaults.
Example
FREQUENCIES VAR=V1 /PERCENTILES=10 25 33.3 66.7 75.
• FREQUENCIES requests the values for percentiles 10, 25, 33.3, 66.7, and 75 for V1.
NTILES Subcommand
NTILES calculates the percentages that divide the distribution into the specified number of
categories and displays the values below which the requested percentages of cases fall. There
are no default ntiles.
• Multiple NTILES subcommands are allowed. Each NTILES subcommand generates separate
percentiles. Any duplicate percentiles generated by different NTILES subcommands
are consolidated in the output.
Example
FREQUENCIES VARIABLE=V1 /NTILES=4.
• FREQUENCIES requests quartiles (percentiles 25, 50, and 75) for V1.