Final answer:
The total number of students involved in the study can be found by summing up all the frequencies of the responses in the provided frequency distribution, but the actual data is needed to give a precise number.
Step-by-step explanation:
To determine how many students were involved in the stress questionnaire study from an introductory statistics class, we need to sum up the frequencies of the responses given in the frequency distribution. Unfortunately, the actual frequency distribution is not provided in the question. To answer your question accurately, we would need the data showing how many students chose each stress score from 0 to 10. Once this information is obtained, you would add up all the frequencies to get the total number of students who participated in the study.