American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Which type of data is analyzed using the chi-squared test?

1. Quantitative

2. Ordinal

3. Nominal

4. Continuous

The correct answer is: Nominal

The chi-squared test is specifically designed to analyze nominal data. Nominal data consists of categories without any inherent order or ranking; examples include gender, race, and yes/no responses. The chi-squared test assesses whether there is a statistically significant association between two categorical variables by comparing the observed frequencies in categories to the frequencies expected under the null hypothesis of independence. In contrast, quantitative and continuous data involve numerical values and typically require different statistical tests, such as t-tests or ANOVA, to analyze relationships or differences. Ordinal data, while also categorical, includes a defined order but does not have equal intervals between categories, making it more appropriate for tests like the Mann-Whitney U test rather than the chi-squared test. Thus, nominal data is the most suitable type for analysis through the chi-squared test.