Instructions to question:
Find the maximum sample size required to estimate a population proportion or percentage.
Question:
Cell phones: As a newly hired manager of a company that provides cell phone services, you want to determine the percentage of adults in your state who live in a household with cell phones and no land-line phones. How many adults must you survey? Assume that you want to be 90% confident that the sample percentage is within four percentage points of the true population percentage.
a) Assume that nothing is known about the percentage of adults who live in a household with cell phones and no land-lines phones.
b) Assume that a recent survey suggests that about 8% of adults live in a household with cell phones and no land-line phones.
Please i need help so badly on this question. Step-step working please.