The number of subjects who participated in the study, given the degrees of freedom would be 20 participants.
How to find the number of subjects ?
In statistics, the degrees of freedom (df) for a t-statistic in a matched-subjects (paired samples) experiment can be calculated as follows:
df = N - 1
Where:
df represents the degrees of freedom.
N represents the number of paired subjects or pairs.
This question has t-statistic with df = 19. To find out how many subjects participated in the study, you can rearrange the formula:
N = df + 1
N = 19 + 1
N = 20
In conclusion, 20 subjects who participated in the matched-subjects experiment.