An Investigation Into An Aspect Of Human Variation

            
             The aim of this investigation was to explore and analyse an aspect of human variation.
            
             There will be a positive correlation between an individual's foot length and their hand span. This may be due to linkage; the genes that create these characteristics may be positioned on the same chromosome so that they become linked, and are inherited together. This linkage causes the two characteristics to become associated so that a person with large feet will also have large hands.
             Variables.
             In order to create a fair investigation, it was necessary to consider the variables that affect an individual's foot length or hand span. Any variables that were likely to disrupt the results were controlled and those measured were recorded accurately so that any correlation could be observed and evaluated successfully.
             i) Age - The majority of individuals stop growing by the age of eighteen. Below this age, people grow at different rates and for this reason, cannot be compared accurately. In this investigation, the sample included only, people above the age of seventeen. Above this age, most people will have attained their maximum growth and therefore their maximum foot length and hand span.
             ii) Gender - The average male is ten centimetres taller than the average female. It follows that this difference will also be translated in an overall trend that males will have greater foot lengths and hand spans. In order to take into account of this variable, equal numbers of males and females were sampled. The results of this investigation have been analysed with males and females together and each gender independently so that any differences across the sexes can be examined and their strength determined.
             iii) Sampling - In order to decide upon the individuals that will be sampled in the investigation, a random sampling technique was applied. In this way individual bias was prevented, creating a fairer experiment. By incorporating a random sampling technique, variables such as race, socio economic groupings and underlying medical conditions, that may have some effect on an individuals foot length or hand span, could be taken into account.