i need help with finding the confidence interval please

david

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Oct 9, 2011
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in a random sample of 250 tv viewers in a large city, 190 had seen a certain controversial program. assuming the population is large compared to the sample size,

a.construct a 95% confidence interval for the true population proportion, using the estimated variance of p^

b/ construct a 95% confidence interval for the true population proportion, using the actual variance of p^

so far i got : p^= 190/250=0.76 and q^=1-p^=0.24

so (p^-p)/ Sp^~N(0,1)

so by using p^-Zc square root (p^q^/n) i got .707<μ<.813

so for part b how do we find the actual variance of p^

everyone please help
 
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