Related Experiment Video
Updated: Aug 4, 2026

Assessment and Communication for People with Disorders of Consciousness
Published on: August 1, 2017
Nonparametric confidence intervals for the one- and two-sample problems
1Department of Biostatistics, University of Washington, Box 357232, Seattle, WA 98195, USA. azhou@u.washington.edu
Abstract:
Confidence intervals for the mean of one sample and the difference in means of two independent samples based on the ordinary-t statistic suffer deficiencies when samples come from skewed families. In this article we evaluate several existing techniques and propose new methods to improve coverage accuracy. The methods examined include the ordinary-t, the bootstrap-t, the biased-corrected acceleration and three new intervals based on transformation of the t-statistic. Our study shows that our new transformation intervals and the bootstrap-t intervals give best coverage accuracy for a variety of skewed distributions, and that our new transformation intervals have shorter interval lengths.
Related Concept Videos
Confidence Intervals
A confidence...
Interpretation of Confidence Intervals
Confidence intervals have confidence coefficients that are crucial for their interpretation. The most common confidence coefficients are 0.90, 0.95, and 0.99, which can be written as percentages–90%, 95%, and 99%, respectively.
Suppose a person calculates a confidence interval with a confidence coefficient of 0.95. In that case, they can...
Confidence Interval for Estimating Population Mean
A confidence interval for the mean is a range of values that provides an estimate of the population mean. As the...
Estimating Population Standard Deviation
Confidence Coefficient
Uncertainty: Confidence Intervals

