Question

What is the 95% confidence interval of E(Y) at X = 4?

Answer 1

Based on the calculations, the 95% confidence interval of E(Y) is equal to 52.3% ± 3.26%.

How to construct a 95​% confidence interval?

Mathematically, a confidence interval of 95% is given by;

α = 1 - 0.95

α = 0.05.

α/2 = 0.05/2 = 0.025.

Next, we would determine the standard deviation of the mean:

Standard deviation of mean = 50/√800

Standard deviation of mean = 1.77.

From the z-table, the z-score of a 95% confidence interval is equal to 1.96.

Confidence interval (0.05, 50, 800) = 1.77 × 1.96

Confidence interval (0.05, 50, 800) = 3.46.

Mathematically, the confidence interval for a mean is given by:

Mean ± (t-critical × (standard deviation/√(sample size)))

Confidence interval = 52.3% ± 3.26%.

Read more on confidence interval here: brainly.com/question/25779324

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Complete Question:

A research team studied Y, the percentage of voters in favor of a candidate. The random variable Y had standard deviation o = 50%. A random sample of 800 voters was selected, and their average was y-bar(800) = 52.3%. What is the 95% confidence interval for E(Y)?