OS-2: Frequency Distributions With Percentile Ranks
DESCRIPTION
OS-2 provides:
- Frequency Distributions
- Means
- Standard Deviations
- Deciles
- Quartiles
for each grade in each building and for each grade in the system.
EXAMPLE: In CTBS Form K Levels 9-14, OS-2 provides, for each grade
in each building:
- Frequency distributions ("FDs") in 3-unit intervals for all
sixteen Standard Scores.
Each frequency distribution presents the number of eligible students
scoring in that interval, with the corresponding percentile rank.
Percentile ranks indicate the percentage of students in that group
whose scores fall below the mid-point of a given score interval.
- Mean, Standard Deviation, Quartiles and first
and ninth Deciles, for each of the 12 subtests, the 3 test
totals (LT, MT, ST) and the composite.
For CTBS Form K Levels 9-14, OS-2 also provides, for each grade in the
system:
- Frequency distributions in 1-unit intervals for all sixteen
Standard Scores, as described above
- Means, Standard Deviations, Quartiles and first
and ninth Deciles, as described above
CCAT: OS-2 report is based on Standard Age Scores, and the buildings'
reports have a 2-unit SAS interval.
GMRT: OS-2 report is based on Grade Equivalent Scores.
When there is only one building in your order, the system's FDs supersede
the building's FDs, and building reports are not printed.
OS-2 is intended for systems that have at least 25 students in each grade,
therefore:
- For the buildings' FDs, if the number of students in a column is
less than 10, the percentiles are reported as "--", and a note appears
on the final sheet.
- For the system's FDs, if the number of students in a column is less
than 25, the percentiles are reported as "--", and a note appears
on the final sheet.
- For all of the FDs, if the number of students in a column is less
than 25, the deciles and quartiles are reported as "n/a", and a note
appears on the final sheet.
Note about "eligible" students: If either of the following are
ordered:
- OS-22 - Exclude Class(es)
from Building/System Averages
- OS-29 - Exclude Student(s)
from Class, Building, System Averages
some classes and/or students may be excluded from the frequency distributions.
RELATED SERVICES
When OS-3 (Local Norms
Reporting Service) is ordered, the Local Percentile Ranks are the same
as the percentiles that appear on the system's OS-2 Frequency Distributions.
