# Top Assumptions for Running a Chi-Square Test ## Introduction

The chi-square test is basically a test that is related to statistical investigation which is used in comparing the observed results with the expected results in the SPSS data analysis. The primary purpose of the square analysis is to determine that if there is a difference between the observed data and the expected data or not due to the chance and if this difference is due to the relationship in between all the variables that are applied or not. Other than the chi-square test, there are two more tests named – T test and Z test. All of these three are somehow related with each other but there are differences among each of them.

## Assumptions of Chi-Square Test

The difference between the chi-square test and the t-test is that the t-test is simply a null hypothesis applied in the statistical hypothesis test most often regarding the two means – first is that it tests that the hypothesis test of the two means is equal or not and the second is that the difference in between them is zero or not. Whereas, the z-test is generally used only for the purpose when there is given a standard of deviation along with the data, which can be larger than the size of 30. Apart from these two tests, the chi-square test is also a type of null hypothesis in the chi-square statistic hypothesis about the relationship among the two variables but the difference is that it is used only at that time when the two categorical variables are independent apart from each other and also belongs to the same population at the same time. The Chi-square test spss, a hypothesis testing method involves two of the most common Chi-square tests that check if the observed frequencies involved in one or more categories are matching with the expected frequencies or not. The “Chi” is a Greek word whose symbol is “χ”. There are lots of assumptions of the chi-square test spss, but few of the top assumptions can be included as –

There are only 2 variables where both of them are usually measured as different categories the nominal level but the data can be the ordinal data. The intervals or the data ratio which is collapsed into the ordinal categories can be used too with the Chi-square to have no rule regarding the cell numbers limitation.

The data filled in the cells must be in frequencies or in any counts of the cases rather than just in the percentages or in some of the other transformations of the sample data collected.

Each of the subjects of this test can contribute the data to the one and only in one cell of the χ2. As an example, if the same subjects are being tested over and over again in the given time then such the comparisons come up of the same subjects at the Time 1, Time 2, Time 3, etc. and whatever more time are given which the χ2 might not be used with.

The expected cell value should be either 5 or more than 5 among at least 80% of the total cells with that no cell should be expected to be less than one. This assumption can only be fulfilled if the sample size is equal to at least the number of total cells then multiplied by 5. This assumption essentially can be specified with the number of sample size cases to use the χ2 for any of the number of cells in that χ2

Here the study groups needs to be independent so that different tests can be used differently when the two groups are related. ## Conclusion

The Chi-square test of independence SPSS is one of the most often applied statistics for testing the case hypotheses when there are nominal variables that often occurs in the clinical research work. The “Chi” is a Greek word whose symbol is “χ”.The chi-square test is also a type of null hypothesis in the chi-square statistic hypothesis about the relationship among the two variables but the difference is that it is used only at that time when the two categorical variables are independent apart from each other and also belong to the same population at the same time.