Figure 8 displays cronbach s alpha that would result if a given item were deleted. Calculating cronbachs alpha in spss improving internal. However, the value of cronbach s alpha for other variables captured with 5point likert scale are above. Cronbach s alpha reliability coefficient normally ranges between 0 and 1. Cronbach s alpha coefficient increases either as the number of items variables increases, or as the average interitem correlations increase i. Cara uji reliabilitas spss alpha cronbachs data kuesioner. Full output and interpretation is provided for all the sub parts. Listwise deletion based on all variables in the procedure. Like the itemtotal correlation presented above in b, this column of information is valuable for determining which items from among a set of items contributes to the total alpha. Where this is the case then i want all missing values on that scale replaced by the average of the nonmissing items on that scale. A testretest reliability coefficient was calculated on this individual statement item since individual items can not have a cronbachs alpha. It is equivalent to performing the split half methodology on all combinations of these items. Cronbachs alpha calculation and interpretation using spss.
This guide shows you the procedure as well as the output. For example, suppose you wish to test the internal reliability of ten variables, v1 through v10. Now when you enter the response for item 4 into spss, you need to reverse the entry, for instance if the respondent has said 5, you will enter 1 into spss, similarly 4 will be exchange with 2 and vice versa. The solution provides the interpretation and calculation of cronbach s alpha using spss. Spss workbook 2 descriptive statistics accuracy of data input once you have entered your data into spss, you need to cleanup the data. Cronbachs coefficient alpha estimates the reliability of this type of scale by determining the internal consistency of the test or the average correlation of items within the test cronbach, 1951. Computing cronbachs alpha in spss with missing data the. The data editor the data editor is a spreadsheet in which you define your variables and enter data. Spss windows there are six different windows that can be opened when using spss.
This involves ensuring that data has been correctly entered. Finally, column seven gives cronbachs for the test scale, which consists of all but the one item. Stepbystep instructions on how to run cronbachs alpha in spss statistics using a relevant example. I used both spearman brown prophecy formula and also used the sum of item variance over total variance formula to calculate the cronbach alpha. This solution mainly discussed cronbach s alpha with four subscales. This edition applies to ibm spss statistics 20 and to all subsequent releases and. With these data now consider how one calculates in spss cronbach s alpha for both scales, task value and. Cronbachs alpha in spss statistics procedure, output and. The itemtest and itemrest correlations of price and rep78 are much lower than those of the other items. Reliability statistics cronbachs alpha cronbachs alpha based on standardized items n of items. Uji reliabilitas spss adalah pengujian yang mengukur tingkat konsisten atau kestabilan data kuesioner menggunakan software spss. Pengertian uji reliabilitas menurut sugiarto dan situnjuk 2006, uji reliabilitas reliability adalah pengujian yang menunjukkan apakah suatu instrumen yang digunakan untuk memperoleh. In stata, how do i compute cronbachs alpha statistic to test. In spss, how do i compute cronbachs alpha statistic to test reliability.
As the average interitem correlation increases, cronbachs alpha increases as well holding the number of items constant. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is made up of multiple likerttype scales and items. If the data contain no missing values, all packages i visited converge to the same value. In r, there are several packages that calculate cronbach s alpha. Welcome to the ibm spss statistics documentation, where you can find information about how to install, maintain, and use ibm spss statistics. 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. In spss, how do i compute cronbachs alpha statistic to test. Cronbachs alpha is the most commonly used statistic for determining the internal consistency of measurements, such as items in questionnaire, exam or survey. Each row corresponds to a case while each column represents a variable. In analyzing the data, you want to ensure that these. The following will give a description of each of them.
Scribd is the worlds largest social reading and publishing site. Calculating cronbachs alpha coefficient for internal consistency a single statement item was presented to each student and then this same statement was presented to the student 3 weeks later. Spss statistical package for the social sciences is a statistical analysis and data management software package. Spss can take data from almost any type of file and use them to generate.
Suppose you wish to give a survey that measures job motivation by asking five questions. Cronbachs alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Calculating cronbach s alpha coefficient for internal consistency a single statement item was presented to each student and then this same statement was presented to the student 3 weeks later. This solution is comprised of a detailed explanation of cronbach s alpha. Concepto e implicaciones en las actividades diagnosticas. A testretest reliability coefficient was calculated on this individual statement item since individual items can not have a cronbach s alpha. Cronbach s alpha examines reliability by determining the internal consistency of a test or the average correlation of items variables within the test. Berikut cara melakukan uji reliabilitas spss terhadap data kuesioner. Is it mandatory to have the value of cronbachs alpha above. Calculating, interpreting, and reporting cronbachs alpha. In reliability, the spss command for running a cronbachs alpha, the only options for missing data are to include or exclude userdefined missing data. However, in terms of anxiety produced as a result of having to learn cronbach s alpha, student a provided a rating of 1 to all three items which suggests little to no anxiety for this student.