8. In a random sample of 400 voters, 208 support the new bonding bill. Find the 98% confidence interval for the true proportion of voters who support the bill. Interpret the interval.
8. In a random sample of 400 voters, 208 support the new bonding bill. Find the 98% confidence interval for the true proportion of voters who support the bill. Interpret the interval.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question
![**Exercise: Confidence Interval Calculation for Voter Support**
In a random sample of 400 voters, 208 support the new bonding bill. Find the 98% confidence interval for the true proportion of voters who support the bill. Interpret the interval.
**Explanation:**
To solve this problem, we'll calculate the confidence interval for the proportion of voters who support the bill using the following steps:
1. **Calculate the sample proportion (p̂):**
\[
p̂ = \frac{208}{400} = 0.52
\]
2. **Choose the confidence level:**
The confidence level is 98%, which means we are looking for a z-score associated with this confidence level. For a 98% confidence level, the z-score is approximately 2.33.
3. **Calculate the standard error (SE) for the proportion:**
\[
SE = \sqrt{\frac{p̂(1 - p̂)}{n}} = \sqrt{\frac{0.52 \times 0.48}{400}} \approx 0.02487
\]
4. **Calculate the margin of error (ME):**
\[
ME = z \times SE = 2.33 \times 0.02487 \approx 0.05794
\]
5. **Determine the confidence interval:**
\[
\text{Confidence interval} = p̂ \pm ME = 0.52 \pm 0.05794
\]
\[
\text{Lower bound} = 0.46206
\]
\[
\text{Upper bound} = 0.57794
\]
**Interpretation:**
We are 98% confident that the true proportion of voters who support the new bonding bill is between 46.2% and 57.8%.
**Visual Representation:**
The small diagram on the right is a bell curve, representing the normal distribution. The shaded region under the curve corresponds to the 98% confidence level, showing the range in which the true proportion is likely to fall.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ffcc5d949-8f53-4ec0-8c3e-6a4495e27c79%2Fe52f8f20-5e36-4be8-837c-f9456c8e9dca%2Fn9vodyd_processed.jpeg&w=3840&q=75)
Transcribed Image Text:**Exercise: Confidence Interval Calculation for Voter Support**
In a random sample of 400 voters, 208 support the new bonding bill. Find the 98% confidence interval for the true proportion of voters who support the bill. Interpret the interval.
**Explanation:**
To solve this problem, we'll calculate the confidence interval for the proportion of voters who support the bill using the following steps:
1. **Calculate the sample proportion (p̂):**
\[
p̂ = \frac{208}{400} = 0.52
\]
2. **Choose the confidence level:**
The confidence level is 98%, which means we are looking for a z-score associated with this confidence level. For a 98% confidence level, the z-score is approximately 2.33.
3. **Calculate the standard error (SE) for the proportion:**
\[
SE = \sqrt{\frac{p̂(1 - p̂)}{n}} = \sqrt{\frac{0.52 \times 0.48}{400}} \approx 0.02487
\]
4. **Calculate the margin of error (ME):**
\[
ME = z \times SE = 2.33 \times 0.02487 \approx 0.05794
\]
5. **Determine the confidence interval:**
\[
\text{Confidence interval} = p̂ \pm ME = 0.52 \pm 0.05794
\]
\[
\text{Lower bound} = 0.46206
\]
\[
\text{Upper bound} = 0.57794
\]
**Interpretation:**
We are 98% confident that the true proportion of voters who support the new bonding bill is between 46.2% and 57.8%.
**Visual Representation:**
The small diagram on the right is a bell curve, representing the normal distribution. The shaded region under the curve corresponds to the 98% confidence level, showing the range in which the true proportion is likely to fall.
Expert Solution

Step 1
Here For 98 Percent confidence Interval
From Z NORMAL TABLE
Zc=2.33
And Here given For Support for New Bonding Bill
Sample Size =400=n
No people support New Bonding Bill =X=208
Step by step
Solved in 2 steps with 1 images

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