A sample of households is conducted by selecting numbers randomly from the phone book. In this community 4% of households have no phone, 10% have only cell phones, and 15% have unlisted home phone numbers. This sample is guaranteed to suffer from.

a. undercoverage.
b. false responses. c. nonresponse.

A: undercoverage bias

Step-by-step explanation:

Undercoverage bias occurs in a study or sampling when some elements of the sample population are not represented or inadequately represented.

In this case study, random sampling using phone book will not adequately represent the true size of the population since 4% have no phone, and 15% have unlisted home numbers, while only 10% have only cell phones. This sampling suffers from undercoverage bias

47 - 90 = 43

43 - 180 = x

x = 137