Suppose the poll in the previous question was conducted by email, and those conducting the survey are concerned about the possib
ility of undercoverage, since some people do not use email or have filters that block mass emails. Which of the following is the best way for them to correct for this source of bias (a) Throw this sample out and start over again with a better sampling method. (b) Use a higher confidence level, such as 99%. (c) Use a lower confidence level, such as 80%. (d) Use a t-interval instead of a z-interval. (e) Take a larger sample.
Throw this sample out and start over again with a better sampling method
Step-by-step explanation:
Biased sampling leads wrong results, since the sample doesn't represent the population which is aimed to be surveyed. Higher/lower confidence level or t distribution cannot correct it.
Confidence level gives the probability of rejecting null hypothesis while it is true. And t-interval is used when the sample size is small or population standard deviation is unknown.
Before choosing confidence level or type of the statistic to infer results, one must follow random sampling not biased.
