A restaurant chain would like to measure the proportion of customers who are generally satisfied with the service provided by its staff. At the end of the meal, as the check is delivered to the table, the server asks those at the table to rate their satisfaction with the service provided as "Very Satisfied,” "Satisfied,” or "Not Satisfied.” During a one-week period, 147 customers were surveyed and 135 (93%) reported they were either Satisfied or Very Satisfied. How might the results be biased in obtaining an estimate of all customers who are satisfied with service?

Because of response bias, the survey results may overestimate the true proportion of satisfied customers.
Because of response bias, the survey results may underestimate the true proportion of satisfied customers.
Because of voluntary response bias, the survey results may overestimate the true proportion of satisfied customers.
Because customers were surveyed over a one-week period, the results should provide an accurate estimate of satisfied customers.


PLEASE HELP