Make a confidence interval for given the following values.
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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Over the first 20 days of the semester, one student is late to class on 6 days. Construct a 98% confidence interval for the true proportion of time this student is late.
A
(0.276, 0.324)
B
(0.131, 0.469)
C
(0.3, 0.7)
D
(0.062,0.538)

1
Identify the sample proportion (p̂) by dividing the number of days the student is late (6) by the total number of days (20). This gives p̂ = 6/20.
Determine the standard error (SE) of the sample proportion using the formula: SE = sqrt((p̂ * (1 - p̂)) / n), where n is the sample size (20).
Find the z-score corresponding to a 98% confidence level. For a two-tailed test, this is typically around 2.33.
Calculate the margin of error (ME) by multiplying the z-score by the standard error: ME = z * SE.
Construct the confidence interval by adding and subtracting the margin of error from the sample proportion: CI = (p̂ - ME, p̂ + ME).
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