• Title/Summary/Keyword: Confidence Interval

Search Result 2,668, Processing Time 0.033 seconds

Theoretical Considerations for the Agresti-Coull Type Confidence Interval in Misclassified Binary Data (오분류된 이진자료에서 Agresti-Coull유형의 신뢰구간에 대한 이론적 고찰)

  • Lee, Seung-Chun
    • Communications for Statistical Applications and Methods
    • /
    • v.18 no.4
    • /
    • pp.445-455
    • /
    • 2011
  • Although misclassified binary data occur frequently in practice, the statistical methodology available for the data is rather limited. In particular, the interval estimation of population proportion has relied on the classical Wald method. Recently, Lee and Choi (2009) developed a new confidence interval by applying the Agresti-Coull's approach and showed the efficiency of their proposed confidence interval numerically, but a theoretical justification has not been explored yet. Therefore, a Bayesian model for the misclassified binary data is developed to consider the Agresti-Coull confidence interval from a theoretical point of view. It is shown that the Agresti-Coull confidence interval is essentially a Bayesian confidence interval.

A Short Consideration of Binomial Confidence Interval (이항신뢰구간에 대한 소고)

  • Ryu, Jea-Bok
    • Communications for Statistical Applications and Methods
    • /
    • v.16 no.5
    • /
    • pp.731-743
    • /
    • 2009
  • The interval estimation for binomial proportion has been treated practically as well as theoretically for a long time. In this paper we compared the properties of major confidence intervals and summarized current issues for coverage probability and interval length which are the criteria of evaluation for confidence interval. Additionally, we examined the three topics which were considered in using the binomial confidence interval in the field. And finally we discussed the future studies for a low binomial proportion.

Interval Estimations for Reliablility in Stress-Strength Model by Bootstrap Method

  • Lee, In-Suk;Cho, Jang-Sik
    • Journal of the Korean Data and Information Science Society
    • /
    • v.6 no.1
    • /
    • pp.73-83
    • /
    • 1995
  • We construct the approximate bootstrap confidence intervals for reliability (R) when the distributions of strength and stress are both normal. Also we propose percentile, bias correct (BC), bias correct acceleration (BCa), and percentile-t intervals for R. We compare with the accuracy of the proposed bootstrap confidence intervals and classical confidence interval based on asymptotic normal distribution through Monte Carlo simulation. Results indicate that the confidence intervals by bootstrap method work better than classical confidence interval. In particular, confidence intervals by BC and BCa method work well for small sample and/or large value of true reliability.

  • PDF

Balanced Accuracy and Confidence Probability of Interval Estimates

  • Liu, Yi-Hsin;Stan Lipovetsky;Betty L. Hickman
    • International Journal of Reliability and Applications
    • /
    • v.3 no.1
    • /
    • pp.37-50
    • /
    • 2002
  • Simultaneous estimation of accuracy and probability corresponding to a prediction interval is considered in this study. Traditional application of confidence interval forecasting consists in evaluation of interval limits for a given significance level. The wider is this interval, the higher is probability and the lower is the forecast precision. In this paper a measure of stochastic forecast accuracy is introduced, and a procedure for balanced estimation of both the predicting accuracy and confidence probability is elaborated. Solution can be obtained in an optimizing approach. Suggested method is applied to constructing confidence intervals for parameters estimated by normal and t distributions

  • PDF

Sequential Estimation of variable width confidence interval for the mean

  • Kim, Sung Lai
    • Journal of the Chungcheong Mathematical Society
    • /
    • v.14 no.2
    • /
    • pp.47-54
    • /
    • 2001
  • Let {Xn, n = 1,2,${\cdots}$} be i.i.d. random variables with the only unknown parameters mean ${\mu}$ and variance a ${\sigma}^2$. We consider a sequential confidence interval C1 for the mean with coverage probability 1-${\alpha}$ and expected length of confidence interval $E_{\theta}$(Length of CI)/${\mid}{\mu}{\mid}{\leq}k$ (k : constant) and give some asymptotic properties of the stopping time in various limiting situations.

  • PDF

Efficient Anomaly Detection Through Confidence Interval Estimation Based on Time Series Analysis

  • Kim, Yeong-Ju;Jeong, Min-A
    • International journal of advanced smart convergence
    • /
    • v.4 no.2
    • /
    • pp.46-53
    • /
    • 2015
  • This paper suggests a method of real time confidence interval estimation to detect abnormal states of sensor data. For real time confidence interval estimation, the mean square errors of the exponential smoothing method and moving average method, two of the time series analysis method, were compared, and the moving average method with less errors was applied. When the sensor data passes the bounds of the confidence interval estimation, the administrator is notified through alarms. As the suggested method is for real time anomaly detection in a ship, an Android terminal was adopted for better communication between the wireless sensor network and users. For safe navigation, an administrator can make decisions promptly and accurately upon emergency situation in a ship by referring to the anomaly detection information through real time confidence interval estimation.

Interval Estimation for a Binomial Proportion Based on Weighted Polya Posterior (이항 비율의 가중 POLYA POSTERIOR 구간추정)

  • Lee Seung-Chun
    • The Korean Journal of Applied Statistics
    • /
    • v.18 no.3
    • /
    • pp.607-615
    • /
    • 2005
  • Recently the interval estimation of a binomial proportion is revisited in various literatures. This is mainly due to the erratic behavior of the coverage probability of the will-known Wald confidence interval. Various alternatives have been proposed. Among them, Agresti-Coull confidence interval has been recommended by Brown et al. (2001) with other confidence intervals for large sample, say n $\ge$ 40. On the other hand, a noninformative Bayesian approach called Polya posterior often produces statistics with good frequentist's properties. In this note, an interval estimator is developed using weighted Polya posterior. The resulting interval estimator is essentially the Agresti-Coull confidence interval with some improved features. It is shown that the weighted Polys posterior produce an effective interval estimator for small sample size and a severely skewed binomial distribution.

Why is 90% Confidence Interval Used When Confidence Interval Approach is Used for Testing Equivalence? (동등성 시험을 신뢰구간을 사용하여 검정하는 경우 왜 신뢰도 90%인 신뢰구간을 사용하는가?)

  • Kang, Seung-Ho
    • The Korean Journal of Applied Statistics
    • /
    • v.21 no.5
    • /
    • pp.867-873
    • /
    • 2008
  • It is a convention to use 5% significance level when a statistical test is employed for clinical data. But when a confidence interval is used for testing equivalence, 90% confidence interval has often been used. When $1-{\alpha}$ confidence interval is used for hypothesis testing, its significance level is often ${\alpha}$. So it makes a confusion that the significance level is 10% if 90% confidence interval is employed for testing equivalence. In this paper I will clarify this issue by reviewing relevant papers and conducting simulation studies. I hope that it will be beneficial to statisticians in pharmaceutical companies, CROs, university hospitals.

Likelihood Based Confidence Intervals for the Difference of Proportions in Two Doubly Sampled Data with a Common False-Positive Error Rate

  • Lee, Seung-Chun
    • Communications for Statistical Applications and Methods
    • /
    • v.17 no.5
    • /
    • pp.679-688
    • /
    • 2010
  • Lee (2010) developed a confidence interval for the difference of binomial proportions in two doubly sampled data subject to false-positive errors. The confidence interval seems to be adequate for a general double sampling model subject to false-positive misclassification. However, in many applications, the false-positive error rates could be the same. On this note, the construction of asymptotic confidence interval is considered when the false-positive error rates are common. The coverage behaviors of nine likelihood based confidence intervals are examined. It is shown that the confidence interval based Rao score with the expected information has good performance in terms of coverage probability and expected width.

The Influence of Extreme Value in Binomial Confidence Interval (이항 신뢰구간에서 극단값의 영향)

  • Ryu, Jea-Bok
    • Communications for Statistical Applications and Methods
    • /
    • v.18 no.5
    • /
    • pp.615-623
    • /
    • 2011
  • Several methods are used in interval estimation for binomial proportion; however the coverage probabilities of most confidence intervals depart from the confidence level when the binomial population proportion closes to 0 or 1 due to the extreme value. Vollset (1993), Agresti and Coull (1998), Newcombe (1998), and Brown et al. (2001) suggested methods to adjust the extreme value. This paper discusses the influence of extreme value in a binomial confidence interval through the numerical comparison of 6 confidence intervals.