The jackknife statistic and its use in setting approximate confidence intervals

  • 45 Pages
  • 1.39 MB
  • English
Statementby Robert Fritz Feistel.
LC ClassificationsMicrofilm 40995 (H)
The Physical Object
Paginationiv, 45 leaves.
ID Numbers
Open LibraryOL1827567M
LC Control Number89894654

Arvesen () gives a class of statistics to which the jackknife may be profitably applied to obtain asymptotic tests or confidence intervals.

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If θ is estimated by θ ⌢ n o, and θ ⌢ n o is based on a U -statistic, or a function of several U -statistics, then the asymptotic t Cited by: Be the estimate of theta that you obtain, where you use the n - one observations obtain by deleting observation i. And then, let's let thta bar be the average of the leave one out estimates.

So, with that notation in mind, the jackknife estimate of the bias of our statistic theta hat, is just n. The jackknife statistic and its use in setting approximate confidence intervals book 8. Coverage Frequencies for Jackknife Confldence Intervals.

As a test of the jackknife confldence interval (3), we gener samples of size n = 20 from the probability distribution 12x(1¡x)2 on the unit interval (0;1). (This is a beta density with parameters fi = 2 and fl = 3.) For each sample of s we compute the jackknife The %JACK and %BOOT macros do jackknife and bootstrap analyses for simple random samples, computing approximate standard errors, bias-corrected estimates, and confidence intervals assuming a normal sampling distribution.

Details The jackknife statistic and its use in setting approximate confidence intervals FB2

In general, the jackknife cannot be extended to calculate confidence intervals or test hypotheses (Efron ). Some attempts have been made to construct confidence intervals by assuming a. Jackknife resampling is applied to bucketed data to calculate the sample variance of the percent change of a metric.

Two-tailed significance testing is then run using the 95% confidence interval. samples and is worth further investigation in view of its more efficient and systematic use of the resamples. In Section 8 the weighted jackknife method of Section 4 is extended to regression M-estimators, nonlinear regression and generalized linear models.

The only essential change for the last two models is in the choice of weights, i.e. The area between each z* value and the negative of that z* value is the confidence percentage (approximately).

For example, the area between z*= and z= is approximately Hence this chart can be expanded to other confidence percentages as well. The chart shows only the confidence percentages most commonly used. The table of Gwet agreement statistics is given next. Since the response is considered nominal, no weight matrix was specified.

As a result, the AC 1 statistic is produced. The AC 1 estimate is If the raters are considered fixed, so that inference is limited to the observed set of raters but subjects are considered randomly sampled from an infinite population, then AC 1 is significantly.

Use of jackknife resampling techniques to estimate the confidence intervals of fMRI parameters.

Description The jackknife statistic and its use in setting approximate confidence intervals FB2

Biswal BB(1), Taylor PA, Ulmer JL. Author information: (1)Biophysics Research Institute, Medical College of Wisconsin, MilwaukeeUSA. [email protected] However a confidence interval for θ is usually preferable. This section, which is highly speculative in content, concerns setting approximate confidence intervals in small sample nonparametric situations.

We begin on familiar ground: setting a confidence interval for the median of a distribution F on the real line. The typical value theorem. The basic idea behind the jackknife variance estimator lies in systematically recomputing the statistic estimate, leaving out one or more observations at a time from the sample set.

From this new set of replicates of the statistic, an estimate for the bias and an estimate for the variance of the statistic. The linkage is recalculated with the i th individual removed from the data set.

Jackknife confidence intervals will take Stein C. The jackknife estimate of variance. Ann Stat 9. the jackknife procedure, used to estimate biases of sample statistics and to estimate variances, and; cross-validation, in which the parameters (e.g., regression weights, factor loadings) that are estimated in one subsample are applied to another subsample.

For more details see bootstrap resampling. One way of finding an estimate is to use a second level bootstrap, this is rather expensive compuation-wise: one could prefer as an intermediate solution a jackknife estimate.

Compute the original estimate of: THETA(0) For b=1 to B do: Generate a sample ; Compute the estimate of based on: THETA(b). Statistical developments in reliability theory 71 Definition of reliability concepcs 76 Parametric methods used in setting confidence limits 79 for systetr availability Jackknifing the availability estimate 84 Monte Carlo simulation studies: New results rn the 88 availability ratio.

For parsimony analyses, the most common way to estimate confidence is by resampling plans (nonparametric bootstrap, jackknife), and Bremer support (Decay indices). The recent literature reveals that parameter settings that are quite commonly employed are not those that are recommended by theoretical considerations and by previous empirical studies.

The optimal search strategy to be. - A location statistic other than the mean Bootstrapping, a data-based simulation method for assigning measures of accuracy to statistical estimates, can be used to produce inferences such as confidence intervals without knowing the type of distribution from which a sample has been taken.

Jackknife confidence intervals. The delete-one jackknife relies on resamples that leave out one entity of the sample at a time, where entities are those individuals that are randomly sampled from the population.

Following Smyth et al., a pseudo-values approach was used to calculate the jackknife CIs. Bootstrapping has been used to estimate confidence intervals for production estimates for both populations and communities calculated by both the size-frequency and instantaneous growth methods (Morin et al.

Huryn b, ). Estimates of confidence intervals (CI) are derived by randomly resampling each of the original data sets used to. The commonly used confidence level is 95% confidence level. However, other confidence levels are also used, such as 90% and 99% confidence levels. Confidence Interval Formula.

The confidence interval is based on the mean and standard deviation. Thus, the formula to find CI is. X̄ ± Zα/2 × [ σ / √n ] Where. X̄ = Mean. Z = Confidence. The book focuses on six common performance metrics: for each metric, statistical methods are derived for a single system that incorporates confidence intervals, hypothesis tests, sample size.

Statistics is a subject of many uses and surprisingly few effective practitioners. The traditional road to statistical knowledge is blocked, for most, by a formidable wall of mathematics.

The approach in An Introduction to the Bootstrap avoids that wall. It arms scientists and engineers, as well as statisticians, with the computational techniques t. Bias Corrected and Accelerated (BCa) Confidence Intervals. BCa intervals require estimating two terms: a bias term and an acceleration term.

Bias is by now a familiar concept, though the calculation for the BCa interval is a little different. For BCa confidence intervals, estimate the bias correction term, \(\hat{z}_0\), as follows: \. Among the most useful, and most used, of statistical constructions are the standard intervals ^ z()˙;^ () giving approximate con dence statements for a parameter of interest.

Here ^ is a point estimate, ^˙ an estimate of its standard error, and z() the th quantile of a standard normal distribution.

This technique can be used to estimate the standard error of any statistic and to obtain a confidence interval (CI) for it. Bootstrap is especially useful when CI doesn't have a closed form, or it has a. The set of parameters is no longer fixed, and neither is the distribution that we use.

It is for this reason that nonparametric methods are also referred to as distribution-free methods. Nonparametric methods are growing in popularity and influence for a number of reasons. This paper introduces the jackknife+, which is a novel method for constructing predictive confidence intervals.

Whereas the jackknife outputs an interval centered at the predicted response of a test point, with the width of the interval determined by the quantiles of leave-one-out residuals, the jackknife+ also uses the leave-one-out predictions at the test point to account for the variability.

The smallest and largest values that remain are the bootstrapped estimate of low and high 95% confidence limits for the sample statistic. In this example, the th and th centiles of the means and medians of the thousands of resampled data sets are the 95% confidence limits for the mean and median, respectively.

I am attempting to use from R's boot package to calculate bias- and skew-corrected bootstrap confidence intervals from a parametric bootstrap. From my reading of the man pages and experimentation, I've concluded that I have to compute the jackknife estimates myself and feed them intobut this isn't stated explicitly anywhere.I haven't been able to find other documentation.

Confidence Interval for a Population Mean: Student’s t-Statistic (Unknown Variance). Suppose a pharmaceutical company must estimate the average increase in blood pressure of patients who take a certain new drug.

Assume that only six patients (randomly selected from the population of all patients) can be used in the initial phase of human testing.One sample mean tests are covered in Section of the Lock 5 textbook.

Concerning one sample mean, the Central Limit Theorem states that if the sample size is large, then the distribution of sample means will be approximately normally distributed with a standard deviation (i.e., standard error) equal to \(\frac{\sigma}{\sqrt n}\).In this course, a "large" sample size will be defined as one.

Bias Corrected and Accelerated (BCa) Confidence Intervals. BCa intervals require estimating two terms: a bias term and an acceleration term. Bias is by now a familiar concept, though the calculation for the BCa interval is a little different. For BCa confidence intervals, estimate the bias correction term, \(\hat{z}_0\), as follows.