Title in English:
The Effect Of Sample Size And It's Selection Methods On
Abstract in English:
The Effect Of Sample Size And It's Selection Methods On
The Psycho-metric Properties Of Psycho-scales.
By:
Ramzi Hasan Al-shinbari
Supervisor:
Prof.D.: Kamil Thamir Al-kubaisi
Abstract
This study aims to investigate the effect of sample size and the way of selecting it on the psychometric properties of the psychological scales and their items which are characterized by the discrimination index of the items, their reliability coefficient, scale reliability and validity, in addition to frequency distribution.
To fulfill this goal, four samples had been chosen randomly with different sizes (400, 200, 122, 30) members and by the occasional sample.
The study adopted (Goldberg’s) Psychic Health Scale , where it is executed on random simple sample size and occasional sample synchronized with Psychic Tension Scale. Then the sample members responses were analyzed according to psychometric properties for the scale and its items on all samples.
The study also shows that (400) members in the simple random sample gave more better properties for the standard compared with other sizes.
(200) size could be used also in random simple sample, especially in calculating the psychometric properties for the items.
The study recommends the use of simple random sample in calculating items psychometric properties in general.
As well as, it recommends also with the possibility of occasional sample use, If it was small size around (30) member.
It is preferable that the size of the psychometric sample properties in psychological scales not less than (400) members , especially in calculating psychometric properties for the items.
Key Words: Sample Size , Selection Methods, Simple random sample, Occasional sample , Psychometric Properties .
