Complete the sentences to form the correct statements about sampling. If a sample is not random, then it is . It is very common to experience when data are collected using surveys. occurs when individuals ask to be included in a survey.

In a survey of 1015 adults, a polling agency asked, "when you retire, do you think you will have enough money to live comfortably or not. of the 1015 surveyed, 534 stated that they were worried about having enough money to live comfortably in retirement. construct a 90% confidence interval for the proportion of adults who are worried about having enough money to live comfortably in retirement.