Homework SourseConduct a poll for candidate You ask 55 if they support the
Conduct a poll for candidate. You ask 55 if they support the candidate and 295 say they support the claim. What is 95% confidence level for the true rate the candidate has support?
0.641-0.715
0.402-0.485
0.307- 0.391
0.661- 0.744
0.494- o.578
0.326- 0.411
Conduct a poll for candidate. You ask 55 if they support the candidate and 295 say they support the claim. What is 95% confidence level for the true rate the candidate has support?
0.641-0.715
0.402-0.485
0.307- 0.391
0.661- 0.744
0.494- o.578
0.326- 0.411
0.641-0.715
0.402-0.485
0.307- 0.391
0.661- 0.744
0.494- o.578
0.326- 0.411
Solution
Note that
p^ = point estimate of the population proportion = x / n = 0.536363636
Also, we get the standard error of p, sp:
sp = sqrt[p^ (1 - p^) / n] = 0.021263613
Now, for the critical z,
alpha/2 = 0.025
Thus, z(alpha/2) = 1.959963985
Thus,
lower bound = p^ - z(alpha/2) * sp = 0.49468772
upper bound = p^ + z(alpha/2) * sp = 0.578039552
Thus, the confidence interval is
( 0.494 , 0.578 ) [option e]
