Uber · Statistics & Data Analysis
Compare Two Coin Proportions
TrueInterview
October 7, 2026 · 1 min read
You have results from two separate coin-flip experiments:
- Coin A was flipped 100 times and came up heads 40 times.
- Coin B was flipped 1,000 times and came up heads 600 times. Assess whether the probability of heads differs statistically between the two coins. Your answer should state:
- The null and alternative hypotheses.
- The appropriate statistical test.
- The test statistic and an approximate p-value.
- A 95% confidence interval for the difference in head probabilities.
- Any assumptions or caveats, particularly because the sample sizes differ greatly. Overview: This problem tests skill in statistical inference for proportions, covering hypothesis formulation, comparison of two independent samples, confidence interval interpretation, and understanding of p-values and sampling variability.
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