s but also it draws on issues concerning blockades. Thus, replication followed by further item analysis and refining will need to take place before the scale can be successfully validated as a measure of what it claims to be.One reason why there are a number of ambiguous items in terms of the factor onto which they load is that the sample size is insufficient. Klines (1981b) study that factors tend to become unclear if the sample size drops below 100 as the larger the sample, the more the standard error of the correlations are reduced. Guildford (1956) stated that 200 subjects is a preferable minimum, whereas Kline (1999) states that 100 is the absolute minimum sample size for a measure involving factor analysis. In addition, for scales with a large number of items, he advised a participants to item ratio of at least 3:1. Kline (1999) also stated that due to the frequency of sex differences appearing, the scale should ideally be run on two separate samples of 100 males and 100 females.According to Kline (1999), the sample population should also be representative of the population for which the scale is intended. This is important in terms of this study because the sample used consisted entirely of students at the University of Leeds. Therefore, perhaps a more representative sample would have positively affected the outcome of this study, in that the construct of interest may hold greater significance for other sections of society. This is due to the fact that few students actually possess cars and therefore the level of fuel tax is perhaps less significant than for those who own and run cars. In addition he suggested that test-retest reliability should be tested after a three-month gap which would give a better indication of this form of reliability. Guildford (1956) also stated that for five-point scales such as the Likert scale, Pearsons correlation coefficient is not ideally suited because it works more efficiently with scales utili...
