Most items appeared to be worthy of retention, resulting in a decrease in the alpha if deleted. The one exception to this was item 4, which would increase the alpha to. How to test reliability method alpha using spss instruments are valid and reliable research is a necessary condition to obtain highquality research results. The reliability analysis procedure calculates a number of commonly used measures of scale reliability and also provides information about the relationships between individual items in the scale. Cronbachs alpha is the most common measure of internal consistency reliability. Reliability analysis allows you to study the properties of measurement scales and the items that compose the scales. If we use the results from our orthogonal rotation look back at. I perform an independent samples ttest on data that have been simulated to correspond to an actual study done by brody et al. Cronbachs alpha in spss statistics procedure, output. Cronbachs alpha showed the questionnaire to reach acceptable reliability. Remember also that i said we should conduct reliability analysis on any subscales individually. Spss, standing for statistical package for the social sciences, is a powerful.
Calculating total scale scores and reliability spss d. Presentation outline reversing negatively worded items adding up the total. To that end, it is necessary to test the validity and reliability to determine whether the instrument used in the study are valid and reliable. The second is vif, the variance inflation factor, which is simply the reciprocal of the tolerance. How to do statistical analysis for test test reliability of a nominal scale in spss. As such, removal of this item should be considered. It is most commonly used when you have multiple likert questions in a surveyquestionnaire that form a scale and you wish to determine if the scale is reliable.
Upon request, spss will give you two transformations of the squared multiple correlation coefficients. It does not have anything like statas calculator functions, so you have to. Calculating total scale scores and reliability spss. Im looking for tests of stationarity in time series, such as unit root tests, dickeyfuller, dickeypantulla, granger or phillipsperron. I am trying to find out test retest reliability of a questionnaire which measures on nominal scale. Using spss for one sample tests spss isnt as good as stata for one sample tests. Cronbach alpha is a reliability test conducted within spss in order to measure the internal consistency i. Biometrie ubungen in spss medizinische fakultat munster. For example, if the test is increased from 5 to 10 items, m is 10 5 2. Using spss to test for homogeneity of proportions the data set consists of three variables. An instructors guide to understanding test reliability.
How to do statistical analysis for test test reliability. Consider the reliability estimate for the fiveitem test used previously. Using spss for one sample tests university of notre dame. My currently research aims to understanding the relationship between two variables.
Now, you should have reverse scored item 3 see above. And i using a quantitative research, now i distribute the questionnaire to the. If the test is doubled to include 10 items, the new reliability estimate would be. Reliability analysis on spss lets test the reliability of the saq using the data in saq. It is most commonly used when the questionnaire is developed using multiple likert scale statements and therefore to determine if the scale is reliable or not.