To assess reliability of a statistic described as 15%, which aspects should be checked?

• A. The color of the chart
• B. Sample size, confidence interval, sampling method; representativeness
• C. The font size of the report
• D. The weather during data collection

Answer: (B)

Reliability of a percentage estimate comes from how precise and representative the estimate is. To gauge that, focus on three things: the sample size, the confidence interval, and the sampling method.

A larger sample size generally reduces sampling error, making the 15% estimate more stable and trustworthy. The confidence interval shows the range within which the true population value is likely to lie, given a chosen level of confidence; a narrow interval indicates higher precision, while a broad one signals more uncertainty around the 15%. The sampling method reveals how the sample was drawn and whether it fairly represents the population; a biased or unrepresentative sample can distort the result and limit its generalizability.

Extraneous factors like the color of the chart, the font size, or the weather during data collection don’t affect the underlying uncertainty or representativeness of the statistic, so they don’t inform its reliability.

So the aspects that matter are sample size, confidence interval, and sampling method with representativeness.