A researcher carried out an observational study in a university library cafe to see if a subtle nudge changed eating habits. They investigated whether displaying a 'Fresh Selection' promotional card next to a fruit basket influenced the choices of undergraduate and postgraduate students compared to a plain, unlabelled fruit basket.
The researcher recorded the number of selections made during the peak lunchtime period (12:00 pm to 2:00 pm). The data gathered is presented in the table below:
| Undergraduates | Postgraduates | |
|---|---|---|
| Promotional basket | 24 | 16 |
| Plain basket | 12 | 19 |
The researcher used the Chi-square test to analyse the data from this study.
Give one reason why this is the appropriate non-parametric statistical test to use.
