statistical methods for environmental science

... semi-variograms are distributed as one for the uniformtransformed data, four for the indicator variables and four cross semi-variogramsbetween the uniform transform and each of the indicator variables ... These techniques are also discussed in Chapter 10 of the U S Environmental Protection Agency (USEPA) publication, Statistical Methods for Evaluating the Attainment of Cleanup Standards Volume 1: ... suggested for statistically dealing with such observations are oftencumbersome to apply (USEPA, 1996) and if such data are abundant may only beeffectively dealt with via nonparametric statistical methods...

Ngày tải lên: 11/08/2014, 10:22

... of the data exists, the expected values may be estimated from the mar-ginals For example, the formula for chi-square for the four-fold contingency table shown below is Classification II Classification ... Scheffé’s method for post-hoc comparisons; Tukey’s gap test; and Duncan’s multiple range test For further discussion of such testing, see Kirk (1968) Computational formulas for ANOVA can be ... cumbersome for problems of any complexity, and a number of computer programs are available for analyzing various designs The Biomedical Statistical Programs (Ed by Dixon 1967) are frequently used for...

Ngày tải lên: 10/08/2014, 20:20

... Methods for adjusting ambient air quality levels for meteomlogical effects an discussed by Zeldin and Meisel (1978) 16.3 METHODS 16.3.1 Graphical Graphical methods are very useful aids to formal ... Trang 1Statistical Methods for Environmental Pollution Monitoring Richard 0 Gilbert Pacific Northwest Laboratory ... in the pth group For example, in the sequence (23, 24, hace, 6, trace, 24, 24, trace, 23) we have g = 3, I, = 2 for the tied value 23, I, = 3 for the tied value 24, end t, = 3 for the three trace...

Ngày tải lên: 18/02/2014, 04:20

... biological rhythms This article describes a method for the detection and simultaneous comparison of multiple nycthemeral rhythms Methods: A statistical method for detecting periodic patterns in time-related ... algebra perspective we choose a specific set of vectors forming an orthonor-mal basis and change basis Statistical methods are applied to search for single coordinates of the data (rela-tive to the ... satisfying Conclusion Two statistical methods that will enlarge the scientists toolbox for analyzing multi-harmonic oscillations were described As the example demonstrated the methods can be used to...

Ngày tải lên: 10/08/2014, 09:20

... Statistics for environmental science and management / by Bryan F.J Manly p cm Includes bibliographical references and index ISBN l-58488-029-5 (alk paper) 1 Environmental sciences - Statistical methods ... to the statistical methods that will be useful for them in theirwork A secondary aim was to produce a text suitable for a course instatistics for graduate students in the environmental science ... does not extend to copying for general distribution, for promotion, for creating new works, or for resale Specific permission must be obtained in writing from CRC Press UC for such copying Direct...

Ngày tải lên: 11/08/2014, 09:21

... allowed for in the usual equations forvariances Also, random measurement errors from a distribution with a mean of zero will just tend to inflate sample variances, and willtherefore be accounted for ... strata, leading to some further reduction in the standard error Methods for deciding on sample sizes for stratified and other sampling methods arediscussed further in Section 2.13 2.8 Post-Stratification ... sampling for points in a rectangular study region The United States Environmental Protection Agency (1989a)manual on statistical methods for evaluating the attainment of sitecleanup standards recommends...

Ngày tải lên: 11/08/2014, 09:21

... 9.99 for log(CH), giving p = 0.000 for the t-test with 22degrees of freedom; t = 0.970/0.326 = 2.78 for log(NT), giving p =0.011 for the t-test) Finally, the plots of standardized residuals forequation ... Trang 1 CHAPTER 3 Models for Data3.1 Statistical Models Many statistical analyses are based on a specific model for a set ofdata, where this consists of one or more ... test for an effect of the factor an analysis of variance table is set up, which takes the form shown in Table 3.5 Here the sum ofsquares for the factor is just the sum of squares accounted for...

Ngày tải lên: 11/08/2014, 09:21

... Chosen Monitoring Sites For practical reasons the sites for long-term monitoring programs areoften not randomly chosen For example, Cormack (1994) notes thatthe nine sites for the United Kingdom ... ratherlarge Trang 8Table 5.3 Values for pH for lakes in southernNorway with the latitudes (Lat) and longitudes(Long) for the lakes Trang 9Table 5.4 Analysis of variance table for the data on pH levels ... between the mean range for samples of size n and thestandard deviation for samples from a normal distribution Thisrelationship is of the form F = k(n)µR, where µR is the mean rangefor samples of size...

Ngày tải lên: 11/08/2014, 09:21

... variance The form of the data would be as shown in Table 6.1, which is for the case of three control and three impact sites, three samples before the impact, and four samples after the impact For a ... only Hence the control and impact sites were observed for three days before the impact, for three days during the impact (1080 pellets), and for three days after the impact was removed The study ... poison and control sites for the 13trials, for each day of the trials The heavy line is the mean difference for all trials Poison pellets were used at the treated site for days 4, 5 and 6 Figure...

Ngày tải lên: 11/08/2014, 09:21

... complications with statistical tests, the United States Environmental Protection Agency (1989a) recommends that the null hypothesis for statistical tests should depend on the status of a site, ... size for the damaged site and n2 is the sample size for the reference site, sp2 = {(n1 - 1)s12 + (n2 - 1)s22}/(n1 + n2 - 2) is the pooled-sample estimate of variance, s12 is the sample variance for ... and reference sites would have had exactly the same mean for the study variable, even in the absence of any impact on the damaged site Therefore, if large samples are taken from each site, there...

Ngày tải lên: 11/08/2014, 09:21

... be statisticallysignificant if it is tested ignoring the way that it was selected Some type of allowance for multiple testing (Section 4.9) is therefore needed Seethe references given above for ... component, such that there is a long-term tendency for thevalues in the series to increase or decrease (as for the sandwichtern); (b) a seasonal component for series with repeated measurementswithin ... 8.9 Correlogram for the series of sunspot numbers, with the broken horizontal lines indicating the limits on autocorrelations expected for a randomseries of this length 8.4 Tests for Randomness...

Ngày tải lên: 11/08/2014, 09:21

... data transformed to obtain this if necessary These methods are well covered in the text by Cohen (1991) (c) Regression on order statistics methods are alternatives to maximum likelihood methods ... necessary to transform the data to normality before this method is used, in which case the estimates a and b will need to be converted to the mean and standard deviation for untransformed data (d) ... likelihood performs well, with an adjustment for bias with a sample size less than or equal to about 20 (Akritas et al., 1994) In the manual for UNCENSOR, Newman et al (1995) provide a flow chart for choosing...

Ngày tải lên: 11/08/2014, 09:21

... approved analytical method for metals that requires a sample of less than 0.1 gram for microwave digestion Methods currently pending approval employing autoextractors for organic analytes require ... sample sent before taking the aliquot for assay In light of this, one wonders what is really implied in basing a risk assessment for 2,3,7,8-TCDD on the upper 95 percent confidence limit for the mean ... 3/16 inch (see Figure 1.1) Upon the completion of the cleanup effort for total DDT, the larger stone was to be removed from the site for use as fill elsewhere Removal of the stone involves its raking...

Ngày tải lên: 11/08/2014, 10:22

... functional form Techniques useful for judgingthe lack of utility of a functional form are discussed later in this chapter.Some of the functional forms that traditionally have been found useful forcontinuous ... S Lilliefors test corrects for the fact that F(X) is not really known a priori. Dallal and Wilkinson (1986) give an analytic approximation to find probabilityvalues for Lilliefors test For P< ... are presented for ν = 1 to ν = 30 degrees of freedom and for probability valuesranging from 0.90 to 0.9995 Many tables equivalently table 0.10 to 0.0005 for 1 − F(tν ) See Table 2.2 for some example...

Ngày tải lên: 11/08/2014, 10:22

... thelog-normal model provides a reasonable model for the data distribution This isfortuitous, for we recall from the discussion of confidence intervals that for alog-normal distribution, half of the ... geometric mean Therefore, in expectationthe geometric mean and median are the same This permits us to formulatehypotheses in terms of the logarithm of concentration, x, and apply standardstatistical ... “t”-distribution or computer algorithms for computing the cumulative probability function of the “t”-distribution The “P” value for the current example is 0.00003 Therefore, the expected loss in deciding...

Ngày tải lên: 11/08/2014, 10:22

... Table 4.1 shows critical values of r for samples ranging from 3 to 50.For sample sizes greater than 50, we can calculate the Z transformation of r as: [4.3] For large samples, Z has an approximate ... critical values for the Spearman rank correlationcoefficient are the same as those for the Pearson coefficient and are also given inTable 4.1, for sample sizes of 50 and less For samples greater ... observations for each x This will give the correctestimates for R2 (try taking the mean ln(Residue) value for each time in Example 4.1and doing a simple linear regression) and correct standard errors for...

Ngày tải lên: 11/08/2014, 10:22

... interpretation problem for data analysts.” (Helsel, 1990a) Calibration and Analytical Chemistry All measurement methods (e.g., mass spectrometry) for determining chemicalconcentrations have statistically ... normal distribution for the log-transformed concentration We thenmake a guess as to the correct values for µ and σ Once we have made this guess wecan calculate a likelihood for each observed data ... example and use the usual formulae to calculate µ and σ The resulting estimates are µ = 0.3692 and σ = 0.4582 That is, ourestimate for µ is much too large and our estimate for σ is much too small...

Ngày tải lên: 11/08/2014, 10:22

... used for aesthetics purposes Note 2: MCLs considered independently of others Note 3: The maximum contaminant levels for radioactive constituents in potable and personal hygiene water shall conform ... formed on the membrane surfaces.12 Reverse osmosis is a candidate for producing high quality water A combination of several systems, including RO, produced water that met National Committee for ... above) COMPARATIVE PERFORMANCE OF TECHNOLOGIES Many promising technologies for wastewater treatment and water recovery aboard the space station have been described briefly Their performance levels...

Ngày tải lên: 10/08/2014, 20:20

... [Figure 3.1 (c)] were formed at 21.2 wt% Thus ce is the minimum concentration required for the formation of beaded fibers, whereas 2–2.5 times ce may be required for the formation of bead-free ... the ratio between the two energies is Es/Eb ~ (ζ/b)2 34 For the case of Sk

Ngày tải lên: 26/11/2015, 12:55

... 2000) Future Efforts Current and future efforts are expected to focus on procedures that can be performed through naturally occurring orifices Other developments will include procedures for imageguided ... research efforts can be divided into some five areas The first area includes methods for improving organ preservation during transport from donor to recipient A second area includes procedures for lengthening ... 111 CHAPTER THE SOCIAL SCIENCE EXPERT PANEL .115 METHODS .116 LITERATURE REVIEW .117 IMPLICATIONS FOR FUTURE WORK .119 CHAPTER...

Ngày tải lên: 22/03/2014, 13:20