D.19 SPSS (IBM(R) SPSS Statistics 19 Base)

Approximate Cost: Depends on level of licensing and support: Standard Package, $2,300-$13,000 and Premium Package, $6,900-$39,000

Source: IBM (www.ibm.com/software/analytics/spss/products/statistics)

Current Version: v22 (2013)

Operating System Needs:

• IBM SPSS Statistics Base 22 for Windows: Microsoft Windows XP (Vista or Windows 7)
• IBM SPSS Statistics Base 22 for Mac: Apple Mac OS 10.5 (Leopard) or 10.6 (Snow Leopard),

Input Structure: Can accept data from multiple file formats

Overview

SPSS is a high-end, general purpose statistical package with a wide variety of capabilities. Originally developed for analyzing social science data, SPSS is now used in business analytics, medicine, academia, and some environmental settings. Like other general purpose packages, SPSS is not specifically tailored for groundwater analysis, yet can perform many of the tests typically conducted on groundwater data.

These tests include methods to compare groups such as t-tests and one-way analysis of variance (ANOVA)A statistical method for identifying differences among several population means or medians., as well as trend analysis such as linear and nonlinear regression. SPSS also has multivariate methods that can be used to interpret patterns in groundwater data. Typically, multivariate analysis (such as principle component analysis, Q-mode factor analysis, and cluster analysis) examines correlationAn estimate of the degree to which two sets of variables vary together, with no distinction between dependent and independent variables (USEPA 2013b). among variables in terms of a few weighted combinations of the component variables. Multivariate analysis can achieve great efficient compression of the original data, while gaining information to help interpret the environmental geochemical origin of contaminants.

Disclaimer: Statistical functions and capabilities presented for this software package have not been reviewed or verified by IBM.

Add-Ins Available

Multiple add-ins are available for SPSS, including applications for bootstrapping, regression analyses, decision trees and others. SPSS also allows for integration of R to expand the rangeThe difference between the largest value and smallest value in a dataset (NIST/SEMATECH 2012). of available applications. A listing of available software packages is provided on the product website: www.ibm.com/software/analytics/spss/products/statistics.

Ease of Use and Data Import

SPSS Statistics 22 is a comprehensive system for analyzing data that can accept data from almost any type of file and use them to generate tabulated reports, charts, and plots of distributions and trends, descriptive statistics, and complex statistical analyses. This program has simple menus and dialog box selections that make it possible to perform complex analyses without using command syntax.

SPSS has a data editor. This feature is user-friendly and resembles a spreadsheet. Using this feature, you can enter data directly into SPSS. In this editor, the columns represent the variables, and the rows represent the observations. You can also import data from a number of different sources, such as data stored in IBM SPSS Statistics data files; spreadsheet applications (such as Microsoft Excel); database applications (such as Microsoft Access); and text files.

Types of Distributions

SPSS is primarily a tool for data analysis rather than a tool to generate specific kinds of distributional data. The Simulation option, however, offers Monte Carlo simulation of a wide range of standard statistical distributions, including ones common to groundwater analyses like the normal, lognormalA dataset that is not normally distributed (symmetric bell-shaped curve) but that can be transformed using a natural logarithm so that the data set can be evaluated using a normal-theory test (Unified Guidance)., gammaA gamma distribution or data set. A parametric unimodal distribution model commonly applied to groundwater data where the data set is left skewed and tied to zero. Very similar to Weibull and lognormal distributions; differences are in their tail behavior, and the gamma density has the second longest tail where its coefficient of variation is less than 1 (Unified Guidance; Gilbert 1987; Silva and Lisboa 2007)., exponential, Weibull, binomial, and Poisson distributions.

Visualization

This program generates commonly used charts such as scatter plots, histograms, and population pyramids. SPSS can create these charts more easily with Chart Builder. This chart creation interface allows you to create a chart by dragging variables and elements onto a chart creation canvas. The Graphics Production Language (GPL) can be used to customize charts.

Primary Uses for Groundwater Data Analyses

Since SPSS is not tailored for groundwater statistics, it is mostly limited in groundwater applications to standard statistical tests like t-tests, ANOVAone-way analysis of variance, linear regression and their nonparametricStatistical test that does not depend on knowledge of the distribution of the sampled population (Unified Guidance). counterparts. SPSS accommodates upper-tail censored dataValues that are reported as nondetect. Values known only to be below a threshold value such as the method detection limit or analytical reporting limit (Helsel 2005). in survival analysis, but not lower-tail censored values such as nondetectsLaboratory analytical result known only to be below the method detection limit (MDL), or reporting limit (RL); see "censored data" (Unified Guidance)..

Benefits

• easily available

• widely used, with active support community

• most standard statistical methods are available

• click and point interface as well as command interface

Limitations

• cost

• not tailored for groundwater statistical analyses
• not all typical groundwater statistical tests included in base package; must integrate with R and create customized functions

• difficult to produce customized analysis

 

Publication Date: December 2013