Testing the Assumption of Population Homogeneity in the Measurement of Dispositional Optimism: Factor Mixture
1Faculty of Education, University of Macau, Macau, P.R. China.
Abstract:
The assumption of population homogeneity in the measurement of dispositional optimism was examined. U.S. and Canadian respondents (N = 591) completed an optimism scale. Possible population heterogeneity was analyzed using factor mixture modeling. Two major results emerged. First, population homogeneity was not supported: A large class of participants had trouble giving consistent answers to optimism items, optimism and pessimism items, or, especially, pessimism items. Second, after the removal of this problematic class, the correlation between optimism and pessimism was found to be .94, a magnitude large enough to support the assumption of unidimensionality. Although psychometric problems with the measurement of optimism have not been identified previously, this study suggests that the typical measurement of dispositional optimism requires substantial revision. The findings showcase the importance of factor mixture modeling in evaluating the psychometric properties of a measurement scale.
Related Concept Videos
02:20The Small x Assumption
01:15Assumptions of Survival Analysis
01:11Testing a Claim about Mean: Known Population SD
Estimating a population mean requires the samples to be distributed normally. The data should be collected from the randomly selected samples having no sampling bias. The sample size needed to be higher than 30, and most importantly, the population standard deviation should be already known.
In most realistic situations, the population standard deviation is often unknown, but in rare circumstances, when it...
01:24Testing a Claim about Population Proportion
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...
01:21Testing a Claim about Mean: Unknown Population SD
Estimating a population mean requires the samples to be approximately normally distributed. The data should be collected from the randomly selected samples having no sampling bias. There is no specific requirement for sample size. But if the sample size is less than 30, and we don't know the population standard deviation, a different approach is used;...
01:23Mechanistic Models: Compartment Models in Individual and Population Analysis