An extract of green tea (Camellia sinensis) has antioxidant properties. It has been suggested that this extract could protect liver cells against chemical-induced toxicity.
Cultures of liver cells were exposed to increasing concentrations of a chemical pollutant, and the percentage of dead cells was measured. The experiments were performed multiple times either with or without the green tea extract.
The graph shows the results for the two sets of data. Each data point shows the mean ±1 \pm 1\,±1 standard deviation.
A student used Spearman's rank correlation coefficient, rsr_srs, to test for correlation between pollutant concentration and the percentage of dead cells.
Which of the following statements about this correlation shown on the graph is correct?
There is a negative correlation between pollutant concentration and cell mortality in both cases.
Spearman's rank correlation coefficient, rsr_srs, for cells with extract will be between 0 and −1-1−1.
Spearman's rank correlation coefficient, rsr_srs, for cells without extract will be between 0 and +1+1+1.
There is no correlation between pollutant concentration and cell mortality in either case.
