Answer: 271
Step-by-step explanation:
As per given description in the question, we have
Critical value for 90% confidence interval =
[using z-value calculator ]
Margin of error : E= 0.05
Since prior estimate of population proportion is unknown so we take p= 0.5
Formula we use to find the sample size :
[we assume p= 0.50]
i.e.
Simplify :
Therefore , the minimum sample size required = 271