A political candidate has asked you to conduct a poll to determine what percentage of people support her.
If the candidate only wants a 5% margin of error at a 99% confidence level, what size of sample is needed?
Give your answer in whole people.
ME=8%=0.08
CL=90%=1.645
n=?

Respuesta :

Answer:

666

Step-by-step explanation:

From this question,

a = 1-99%

a = 1-0.99

a = 0.01

5% = z(0.05) = 2.58 when we check the standard normal table

Therefore we calculate n as:

n = (z/E)²*p*1-p

Z = 2.58

E = 0.05

P = 0.5

1-p = 0.5

(2.58/0.05)²x0.5x0.5

= 51.6²x0.5x0.5

= 665.64

Therefore n is approximately 666.