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The second confidence interval is always at the confidence level that you specify.or example, if the position is (7,14), the confidence interval is between the 7 th smallest observation and the 14 th smallest observation. The position indicates which observation Minitab uses for the upper and lower bound. The first confidence interval has the highest achievable confidence level that is less than the confidence level that you specify.You should use the shortest interval for which the achieved confidence level is closest to the target confidence level. Because of this, Minitab calculates three confidence intervals with varying levels of precision. The 1-sample sign test does not always achieve the confidence level that you specify because the sign test statistic is discrete. If the interval is too wide to be useful, consider increasing your sample size. Use your specialized knowledge to determine whether the confidence interval includes values that have practical significance for your situation. The confidence interval helps you assess the practical significance of your results. A lower bound defines a value that the population median is likely to be greater than. For example, a 95% confidence level indicates that if you take 100 random samples from the population, you could expect approximately 95 of the samples to produce intervals that contain the population median.Īn upper bound defines a value that the population median is likely to be less than. The percentage of these confidence intervals or bounds that contain the median is the confidence level of the interval. But, if you repeated your sample many times, a certain percentage of the resulting confidence intervals or bounds would contain the unknown population median. Because samples are random, two samples from a population are unlikely to yield identical confidence intervals.
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The confidence interval provides a range of likely values for the population median.