Question

Out of 600 people sampled, 390 preferred Candidate A. Based on this, find a 99% confidence level for the true proportion of the voting population ( p ) prefers Candidate A. Give your answers as decimals, to three places.

Answer 1

Confidence Interval for the true proportion:

Sample Proportion

n : Sample Size : Number of people sampled = 600

Number of people preferred candidate 'A' = 390

Sample Proportion : Sample proportion of people preferred Candidate 'A' = 390/600 = 0.65

Confidence Level	99%
(= 100-99/100=1/100 ) = 0.01	0.01
/2 (=0.01/2=0.005)	0.005
	2.5758

99% confidence level for the true proportion of the voting population ( p ) prefers Candidate A

99% confidence level for the true proportion of the voting population ( p ) prefers Candidate A = (0.600, 0.700)