The aim of this investigation was to look at the reliability and validity of Hans Eysenck's EPI Test. The EPI questionnaire comprises of items of a 'yes/no' variety.

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Abstract

The aim of this investigation was to look at the reliability and validity of Hans Eysenck’s EPI Test. The EPI questionnaire comprises of items of a ‘yes/no’ variety. They are essentially intended as research tools (as opposed to diagnostic tools for use in clinical settings) and, as such, ‘they are regarded as acceptable, reliable and valid’ (Kline 1981, Shackleton and Fletcher, 1984).The Alternative Hypothesis was that there would be a positive correlation between the E and N scores for forms A and B of the EPI. The Null Hypothesis was that there would not be a positive correlation between the scores for forms A and B, and any such found relationship would be down to chance factors operating.

The correlation study was carried out because we were looking for a relationship between the E scores and the N scores for forms A and B of Hans Eysenck’s EPI Test. The independent variable and dependent variable were not operationalised in this case because an experimental method was not being used and this investigation used test re-test reliability. A repeated measure design was used because it was quick, economical and cancelled out individual differences. Eighteen naïve psychology students, male and female were used for this investigation.  An opportunitive sample was used because it was quick, easy and could be carried out in a classroom.

The results, taken from the Raw Score Data table and scatter graph showed evidence of a positive correlation. However, to accept that this result was significant, we subjected the data to further statistical analysis. A Spearman Rho Correlation Coefficient test (Rs) was chosen because the data was Ordinal and parametric assumptions were not met. The outcome stated that with number of people equalling 18 and significance set at p=0.05 for a one tailed test, the calculated value for the ‘E’ score was 0.87 and for the ‘N’ score was 0.90. The critical table value tells us that a value 0.464 and above has a degree of accuracy to 0.05, and a value of 0.622 and above has a degree of accuracy to 0.01. The results of the ‘E’ and ‘N’ score for the E.P.I test were highly significant as they both exceeded the value of 0.622 and were therefore accepted, with the Alternative Hypothesis and rejected the Null.

Introduction

Personality is defined as the totality of a persons attitudes, interests, behavioural patterns, emotional responses and social roles. Epitomising particular character traits that endure over long periods of time.

Many psychologists have many explanations about how our personalities develop. Freud, believes unique individual experiences during the invariant psycho sexual stages of oral, anal, phallic and genital account for different personalities. Whereas, although social learning theorists accept that much of our behaviour results from conditioning by social agents. They also think we learn from observing and imitating certain important  models  around us, for example the primary caregiver.  

Along with theories of how personality came to develop came Personality theories of classification some of which, have been around for centuries. The Ancient Greeks for example believed that there were four types of personality: Sanguine, Choleric, Melancholic and Phlegmatic. Since then there have been numerous theorists attempting to analyse the personality. William Sheldon (1940) classified people on the basis of body build and put them into three categories; Endomorphs who would be soft, round, relaxed and extrovert, Mesomorphs who were athletic and had aggressive tendencies and finally Ectomorphs who were thin, frail and introverted. Due to the complexity of the personality, psychologists moved away from this kind of theory to concentrate on trait theories. For a trait theory to be acceptable as a personality theory it must firstly isolate basic traits which describe personality and measure them accurately.

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This is attempted using a process called Factor Analysis. A pioneer in this field was Raymond Cattell (1965). Cattell believed that the personality could be divided into two kinds: Surface Traits and Source Traits. Surface Traits were those, which other people could see, the overt personality, but underlying these are Source Traits which create the basis of the personality. Although Surface Traits do reflect Source Traits, they vary from person to person. Cattell considered that there were sixteen major source traits which everyone possessed to a lesser or greater degree and from this he developed the personality test known as ...

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