PRESENTATION ONRELIABILITY AND VALIDITY OF SCALE

SUBMITTED TO: Department of business management

DR. Y.S. PARMAR UNIVERSITY OF HORTICULTURE AND FORESTRY NAUNI SOLAN (HP) 173230

Measurement in researchMeasurement in research

Definition-measurement is a process of Definition-measurement is a process of mapping aspects of a domain onto mapping aspects of a domain onto

other aspects of a range according to other aspects of a range according to some rule of correspondence.some rule of correspondence.22

Classifcation of scale

A) nominal scale B) ordinal scale C) interval scale D) ratio scale

Reliability of test scores Stability and test worthiness of score depend

upon the degree to which the score is an index of true ability.

METHODS TO MEASURE RELIABILITYA) test retest (reception) method- the test is given

& repeated on the same group & correlation computed between first & second set of scores.

B) alternate and parallel form method- here the correlation between form a & form b taken as a measure of the self correlation of the test. The co efficient becomes an index of the equivalence of two forms of test.

Cont.. C) the split half method- it is to make

up two sets of scores combining alternate items in the test.

D) the method of rational equivalence- the method of rational equivalence represents an attempt to get an estimate of the reliability of a test, free from the objections raised against the method out- lined above.

The effect upon reliability of lengthening or repeating a test

1) the reliability coefficient from several application or repeatition of a test.

2) the spearman brown formula applied to ratings.

3) lengthening the test to attain a desired degree of reliability.

4) precautions to be observed in using the prophency formula.

Reliability in terms of true score and measurement errors 1) the reliability co-efficient as a

measure of true variance. 2) estimating true scores by way of

regression equation & the reliability coefficient.

3) the index of reliability. 4) the standard error of an obtained

score.

Other factors

A) when is the reliability coefficient satisfactory.

B) the effects of different ranges upon reliability.

C) reliability of speed test. D) reliability at different parts of

the test range.

The validity of test scores

1) determining validity by means of judgements.

2)determinig validity experimentally.3) factorial validity.4) validity and the length of a test.

Four approaches to validation of scale

A) logical validation. B) jury opinion. C) known groups. D) independent criterion.

REFERENCES BOOK- STATISTICS IN PSYCHOLOGY & EDUCATION 1) HENRY E. NARETT, PH.D 2) R.S. WORDWORTH

METHODS IN SOCIAL RESEARCH 1) WILLIAM J. GOODE 2) PAUL K. HATT

RESEARCH METHODOLOGY METHODS AND TECHNIQUES C.R. KOTHARI