I am looking for the 95% confidence interval estimate of the true population for the following:

If the governor election were held today, would you vote for Martinez or Pajcic?

Matinez : 43%
Pajcic: 40%
Undecided: 14%
Don't know: 8%

The sample population consists of 959 voters.

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Here is what I have concluded so far:

The true value would be Martinez since he has the greater percentage of votes so far. And, since it is a 95% confidence level, the Z level must be 1.96.

0.43 (959) = 412 +/- 1.96 [(0.43)(1-0.43)/959]^2 = 412+/- 6.51

Therefore, the upper limit of the interval = 412 + 6.51
and, the lower limit of the interval = 412 - 6.51

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Can anyone tell me if this accurate, please? Thank you in advance.