The statistical definition of abnormality

Question 1

What is the definition of abnormality

Answer 1

By definition, abnormality means deviating from the norm or average.

Question 2

Statistically infrequent behaviour is…?

Answer 2

abnormal

Question 3

Statistically frequent behaviour is…?

Answer 3

normal

Question 4

How is the normal distribution curve made?

Answer 4

It is made by individual characteristics being measured (eg mood, intelligence) and then the distribution of these characteristics within the population will be graphed.

Question 5

On a normal distribution curve, where are the majority of people and what are they defined as?

Answer 5

The majority of people are in the middle and they are defined as normal.

Question 6

On a normal distribution curve, where are the minority of people and what are they defined as?

Answer 6

Few people fall at either end and so are defined as abnormal.

Question 7

How is the spread measured?

Answer 7

The spread is measured by standard deviation.

Question 8

Where does 68% of the population fall?

Answer 8

Between 1SD either side of the mean

Question 9

What percentage of the population fall between 1SD either side of the mean?

Answer 9

68% of the population.

Question 10

Where does 95% of the population fall?

Answer 10

Between 2SD either side of the mean

Question 11

What percentage of the population fall between 2SD either side of the mean?

Answer 11

95% of the population.

Question 12

What percentage of the population fall below and above 2SD? Thus, what are they considered?

Answer 12

2.5% of the population. Thus they are considered abnormal.

Question 13

Where does 2.5% of the population fall? Thus, what are they considered?

Answer 13

Below and above the 2SD. Thus they are considered abnormal.

Question 14

Evaluate in terms of objectivity. (strength)

Answer 14

On strength is that the graph is based upon quantitative data, eg scored on a depression test. The data is therefore viewed as more objective and more scientific. Also does not require personal interpretations, therefore objective and valid.

Question 15

Give an example what could be plotted on a normal distribution curve.

Answer 15

Eg, Normal people eat an average of between 1500 to 3000 cals per day, while anorexics consume very few and bulimics consume lots - making their behaviour abnormal.

Question 16

Where does 2.5% of the population fall? Thus, what are they considered?

Answer 16

Below and above the 2SD. Thus they are considered abnormal.

Question 17

Evaluate in terms of usefulness. (strength)

Answer 17

One strength is that it is useful in that the use of statistical data gives practitioners the evidence needed in order to refer an individual for the treatment they require, eg, if someone scores abnormally high for depression, and are within the 2.5% of the population that are above the 2SD point they are considered abnormal and can therefore get therapy.

Question 18

Evaluate in terms of simplicity. (weakness)

Answer 18

One weakness is that it in too simple as it does not classify whether all behaviour is undesirable, as there are many abnormal behaviours that can be considered desirable such as being abnormally productive, or having an abnormally high IQ. Therefore, in order to identify behaviour that need treatment, there needs to be a means of identifying infrequent yet undesirable behaviours.

Question 19

Evaluate in terms of ethnocentrism. (weakness)

Answer 19

Another weakness is that is is culturally relative and ethnocentric as one symptom of schizophrenia is claiming it hear voices however it is regarded as normal and even desirable in some cultures. Eg, Lee (1969) found that zulu women screamed to themselves for days as a response to unhappiness. Such behaviour would be statistically infrequent in the UK so abnormal, yet very frequent in zulu women to considered normal.