Problem

Assuming the population has a bell-shaped distribution, if a sample size $n=25$ has a sample mean $\bar{x}=32$ with a sample standard deviation $s=2$, find the margin of error (MOE) at a $99 \%$ confidence level. Round the answer to two decimal places. \[ \mathrm{MOE}= \]

Solution

Step 1 :Given a sample size \(n = 25\), a sample mean \(\overline{x} = 32\), and a sample standard deviation \(s = 2\). We are asked to find the margin of error (MOE) at a 99% confidence level. The Z-score for a 99% confidence level is \(Z = 2.576\).

Step 2 :The formula for the margin of error (MOE) is given by \(MOE = Z \cdot \frac{s}{\sqrt{n}}\).

Step 3 :Substitute the given values into the formula: \(MOE = 2.576 \cdot \frac{2}{\sqrt{25}}\).

Step 4 :Solving the above expression gives \(MOE = 1.0304\).

Step 5 :Rounding to two decimal places, the margin of error (MOE) at a 99% confidence level is approximately \(\boxed{1.03}\).

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Source: https://solvelyapp.com/problems/AR8GyiKH2X/

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