A local auto dealership advertises that 90% of customers whose autos were serviced by the service department

Question:

A local auto dealership advertises that 90% of customers whose autos were serviced by the service department are pleased with the results. As a researcher, you take exception to this statement because you are aware that many people are reluctant to express dissatisfaction. A research experiment was set up in which those in the sample had received service by this within the past 2 weeks.During the interview, the individuals were led to believe that the interviewer was new in town and was considering taking his car to this dealer’s service department. Of the 60 sampled, 14 said that they were dissatisfied and would not recommend the department.
a. Estimate the proportion of dissatisfied customers using a 95% confidence interval.
b. Given your answer to part a, what can be concluded about the dealer’s claim?
Dealer
A dealer in the securities market is an individual or firm who stands ready and willing to buy a security for its own account (at its bid price) or sell from its own account (at its ask price). A dealer seeks to profit from the spread between the...