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US Weekly magazine claims that 32% of its readers believe Angelina Jolie was best dressed at the Academy awards. To verify this claim, how large a sample is needed for a 0.05 margin of error at a 95% confidence level?

Respuesta :

JeanaShupp

Answer: 335

Step-by-step explanation:

Formula for sample size :

[tex]n=p(1-p)(\dfrac{z^*}{E})^2[/tex], where p =population proportion, z* = critical z-value, E = Margin of error.

Given: p = 32% = 0.32

E = 0.05

Critical z-value for 95% confidence = 1.96

Required sample size :

[tex]n=(0.32)(1-0.32)(\dfrac{1.96}{0.05})^2\\\\=334.372864\approx335[/tex]

Hence, the required sample size = 335