A researcher has conducted a survey to determine the proportion of the students at UCLA who are interested in a new internet movie streaming service.
The researcher first mailed out surveys to 600 students. 90 responded to the mail survey. Out of these 90 students, 72 students are interested in the new service.
The researcher then used the telephone to contact 150 students out of the 510 students who did not reply to the mail survey. Out of these 150 students contacted by phone, 60 students are interested in the new service. Compute an unbiased estimate of the proportion of the
students of UCLA interested in the new service.