Page 170 - DEDU504_EDUCATIONAL_MEASUREMENT_AND_EVALUATION_ENGLISH

Educational Measurement and Evaluation

Notes 12.5 C-Scores

Meaning of C-Scores

C-scores are those converted scores of raw scores of which the mean (M) is 5 and standard
σ
deviation () is 2. For it, the range of raw scores is distributed into 11 equal unit-groups which
are displayed on a 11-point scale from 0 to 10. These groups are sequential, that is, the scores of
the second group are more than the first one, and the scores of third are more than that of the
second; in the same way, the scores of eleventh group are more than that of the tenth.
Calculation of C-Scores
There are two methods of converting a raw score into C-score— by Z-score and by percentile
rank. The following formula is used to convert a raw scores into C-score by Z-score :
C-score, C = 5 + 2Z
To convert a raw score into C-score by percentile rank (PR), the raw score is first changed into
percentile rank and then C-score is found out using the following Table—3.
Table—3
11-Point C-Score Scale

C-scores Z-scores limits Range of PRs % of Raw % in whole
scores Number

10 More than + 2.25 More than 98.78 1.22 1
9 More than + 1.75 to +2.25 95.99 to 98.78 2.79 3
8 More than + 1.25 to + 1.75 89.44 to 95.99 6.55 7
7 More than + 0.75 to + 1.75 77.34 to 89.44 12.10 12
6 More than + 0.25 to 0.75 59.87 to 77.34 17.47 17
5 Less than - 0.25 to + 0.25 40.13 to 59.87 19.74 20
4 Less than - 0.75 to - 0.25 22.66 to 40.13 17.47 17
3 Less than - 1.25 to - 0.75 10.56 to 22.66 12.10 12
2 Less than - 1.75 to - 1.25 4.01 to 10.56 6.55 7
1 Less than - 2.25 to - 1.75 1.22 to 4.01 2.79 3
0 Less than - 2.25 Less than -2.22

Utility of C-Scores
In some situations in the field of education, the use of C-scores is more useful than the use of Z-
scores and T-scores, however such situations are very rare.
The first demerit of its use is awarding zero score. The second demerit is that there comes much
difference in percentage (%) if C-score goes up or down by even 1 point.

12.6 Stanine Scores

Meaning of Stanine Scores

Stanine scores are those converted scores of raw scores of which the mean (M) is 5 and standard
deviation () it 1.96. For it, the raw scores are divided into 9 unit-groups and they are displayed
σ
on a 9-point scale from 1 to 9. The groups of a Stanine scale are not equal, because this scale is

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