and X = 96, construct a 90% confidence interval for the population proportion, p. Give your answers to three decimals < p <

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**Constructing a 90% Confidence Interval for Population Proportion**

Given:
- Sample size \( n = 120 \)
- Number of successes \( X = 96 \)

**Problem Statement:**
Construct a 90% confidence interval for the population proportion \( p \). Report the interval boundaries to three decimal places.

**Solution Steps:**

1. **Calculate the sample proportion (\( \hat{p} \))**:
   \[
   \hat{p} = \frac{X}{n} = \frac{96}{120} = 0.8
   \]

2. **Find the critical value ( \( Z \) ) for a 90% confidence interval**:
   - For a 90% confidence level, \( Z \approx 1.645 \) (This is the critical value for the standard normal distribution that corresponds to the middle 90% of the distribution.)

3. **Calculate the standard error ( \( SE \) )**:
   \[
   SE = \sqrt{\frac{\hat{p}(1 - \hat{p})}{n}} = \sqrt{\frac{0.8 \times 0.2}{120}} = \sqrt{\frac{0.16}{120}} \approx 0.0365
   \]

4. **Compute the margin of error ( \( ME \) )**:
   \[
   ME = Z \times SE = 1.645 \times 0.0365 \approx 0.0601
   \]

5. **Determine the confidence interval**:
   \[
   \hat{p} \pm ME = 0.8 \pm 0.0601
   \]
   Therefore, the confidence interval is approximately:
   \[
   0.8 - 0.0601 < p < 0.8 + 0.0601
   \]
   \[
   0.740 < p < 0.860
   \]

**Final Answer:**
\[
0.740 < p < 0.860
\]

**Explanation:**

- The interval [0.740, 0.860] means that we are 90% confident that the true population proportion \( p \) lies within this range based on the sample data provided. 
- This interval gives a range of plausible values for the population proportion, reflecting the uncertainty inherent in using
Transcribed Image Text:**Constructing a 90% Confidence Interval for Population Proportion** Given: - Sample size \( n = 120 \) - Number of successes \( X = 96 \) **Problem Statement:** Construct a 90% confidence interval for the population proportion \( p \). Report the interval boundaries to three decimal places. **Solution Steps:** 1. **Calculate the sample proportion (\( \hat{p} \))**: \[ \hat{p} = \frac{X}{n} = \frac{96}{120} = 0.8 \] 2. **Find the critical value ( \( Z \) ) for a 90% confidence interval**: - For a 90% confidence level, \( Z \approx 1.645 \) (This is the critical value for the standard normal distribution that corresponds to the middle 90% of the distribution.) 3. **Calculate the standard error ( \( SE \) )**: \[ SE = \sqrt{\frac{\hat{p}(1 - \hat{p})}{n}} = \sqrt{\frac{0.8 \times 0.2}{120}} = \sqrt{\frac{0.16}{120}} \approx 0.0365 \] 4. **Compute the margin of error ( \( ME \) )**: \[ ME = Z \times SE = 1.645 \times 0.0365 \approx 0.0601 \] 5. **Determine the confidence interval**: \[ \hat{p} \pm ME = 0.8 \pm 0.0601 \] Therefore, the confidence interval is approximately: \[ 0.8 - 0.0601 < p < 0.8 + 0.0601 \] \[ 0.740 < p < 0.860 \] **Final Answer:** \[ 0.740 < p < 0.860 \] **Explanation:** - The interval [0.740, 0.860] means that we are 90% confident that the true population proportion \( p \) lies within this range based on the sample data provided. - This interval gives a range of plausible values for the population proportion, reflecting the uncertainty inherent in using
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