A previous study found that your school consists of White/Caucasian students. You want the confidence interval for the proportion of White/Caucasian students to be no more than away from the true proportion. How many students must you include in a sample to create this confidence interval?
Table of contents
- 1. Introduction to Statistics53m
- 2. Describing Data with Tables and Graphs2h 1m
- 3. Describing Data Numerically1h 48m
- 4. Probability2h 26m
- 5. Binomial Distribution & Discrete Random Variables2h 55m
- 6. Normal Distribution & Continuous Random Variables1h 48m
- 7. Sampling Distributions & Confidence Intervals: Mean2h 8m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 20m
- 9. Hypothesis Testing for One Sample2h 23m
- 10. Hypothesis Testing for Two Samples3h 25m
- 11. Correlation1h 6m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 30m
- 14. ANOVA1h 4m
8. Sampling Distributions & Confidence Intervals: Proportion
Confidence Intervals for Population Proportion
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Make a confidence interval for p given the following values.
x=314,n=500,C=99%
A
(0.560,0.696)
B
(0.572,0.684)
C
(0.572,0.696)
D
(0.560,0.684)

1
Step 1: Identify the given values in the problem. Here, the sample proportion (p̂) is calculated as p̂ = x/n, where x = 314 and n = 500. The confidence level (C) is 99%.
Step 2: Determine the critical value (z*) for a 99% confidence level. This can be found using a z-table or statistical software. For a 99% confidence level, z* is approximately 2.576.
Step 3: Calculate the standard error (SE) of the sample proportion using the formula SE = sqrt((p̂ * (1 - p̂)) / n). Substitute the values of p̂ and n into the formula.
Step 4: Compute the margin of error (ME) using the formula ME = z* * SE. Multiply the critical value (z*) by the standard error (SE) to find the margin of error.
Step 5: Construct the confidence interval (CI) using the formula CI = (p̂ - ME, p̂ + ME). Subtract and add the margin of error (ME) to the sample proportion (p̂) to find the lower and upper bounds of the confidence interval.
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