The survey in the previous question was conducted by calling land-line telephones, and those conducting the survey are concerned about the possibility of under coverage, since some people do not own a phone or own only a cell phone. Which of the following is the best way for them to correct for this source of bias? a. Use a lower confidence level, such as 80%.
b. Use a higher confidence level, such as 99%.
c. Take a larger sample.
d. Use a t-interval instead of a z-interval.
e. Throw this sample out and start over again with a better sampling method.