Instant Biostatistics!
Most statistics programs are designed by statisticians, for
statisticians. These programs are feature-packed and powerful,
but can overwhelm scientists with thick manuals, obscure statistical
jargon and high prices. GraphPad InStat is different. Designed by
a scientist for scientists.
"InStat takes a kinder, gentler approach...All prompts
to the user are in plain English and simple to follow.
The program guides the user through a four-step
process; defining the data type, entering data, choosing
a statistical test, and presenting the results...The user
navigates easily through these steps, to lucid and
complete output...The analysis checklists are a
masterstroke...This small, but effective package is
highly recommended."
John Wass, Statistics, Fast and Easy, Science 282:1652,
Nov 27, 1998.
Four features make InStat stand out from the other
statistics programs.
InStat guides you step by step
InStat conquers the learning curve by escorting you through
statistical analyses. You'll master the program in just a few minutes
-- really.
Clear analysis choices with explanations
You don't have to know the name of the test you need. InStat
helps you pick an appropriate test by asking questions about your
data. If you are unsure, consult the extensive help screens, which
explain the statistical reasoning in plain language.
Easy to understand results
InStat does not assume that you are a statistics whiz. It presents
results in simple paragraphs, with a minimum of statistical jargon.
InStat's help screens review the use of each test and explain every
portion of the results.
Unique analysis checklists
With other statistics software, it is too easy to get the right answer
to the wrong question. That's why InStat provides a unique
analysis checklist. Double-check that your data have not violated
any assumptions of the test, and that you have picked a test that
matches your experimental design and really answers the question
you had in mind.
Feature List
Group comparisons
- Unpaired t test or the nonparametric Mann-Whitney test.
- Welch's unpaired t test (does not assume equal standard
deviations).
- Paired t test or the nonparametric Wilcoxon matched pairs
test.
- Ordinary one-way ANOVA or the nonparametric
Kruskal-Wallis test.
- Repeated measures one-way ANOVA (identical to two-way
ANOVA without replication) or the nonparametric Friedman
test.
- Follow ANOVA with the Bonferroni, Tukey,
Student-Newman-Keuls or Dunnett multiple comparison post
test, or with the post test for linear trend.
- Follow nonparametric ANOVA with Dunn's post test.
- One sample t test or the nonparametric Wilcoxon rank sum
test.
- F test or Bartlett's test to test for equality of standard
deviations.
- Perform unpaired t tests and ordinary ANOVA from either raw
data or mean, N and SD (or SEM).
- Allows missing values in ordinary ANOVA and unpaired t
tests.
- Calculate mean, SD, SEM, minimum, Maximum and median of
each group, and the 95% confidence interval of the group mean.
- Kolmogorov-Smirnov normality test.
- View bar graph of group means and SD or SEM.
Contingency tables
- Chi-square test with or without Yates' continuity
correction.
- Chi-square test for linear trend.
- Fisher's exact test.
- McNemar's test. (Mac only. Also performed by StatMate.)
- Calculate 95% confidence intervals for the relative risk, odds
ratio or difference between two proportions.
- Calculate the sensitivity, specificity,positive predictive value,
negative predictive value and likelihood ratio of a diagnostic test,
with 95% confidence intervals. (Windows version only.)
Linear regression and
correlation
- Calculate slope and intercept with 95% confidence intervals.
- Force the regression line through a specified point.
- Determine new points along the standard curve.
- Calculate correlation coefficient (Spearman or Pearson) and its
confidence interval.
- Test for departure from linearity with a runs test or the F test for
linearity.
- View scatter plot with regression line and its 95% confidence
interval.
Multiple regression
and correlation (Win
only.)
- Calculate a correlation matrix.
- Multiple regression using selected X variables.
- For each X variable, compute its best-fit coefficient with
standard error and 95% confidence interval, and a P value
testing whether the variable contributes significantly to the
model.
- Compute the Variable Inflation Factor (VIF) to test for
multicollinearity (whether the variable is redundant).
Sample size, power
and miscellaneous calculations. Mac only. StatMate (Win)
also performs these calculations.
- Calculate exact P value from z, t, r, F, or chi-square.
- Calculate 95% confidence interval of a count or proportion.
- Calculate sample size needed to obtain a significant difference
when comparing two groups or two proportions.
- Calculate sample size needed to narrow a confidence interval to
a specified width for one mean, one proportion, or the
difference of two means or two proportions.
Program features
- Enter up to 1000 (Windows) or 500 (Mac) rows and 26
columns of data.
- Mathematically transform selected data (i.e., logarithm,
reciprocal, logit, etc.).
- Transpose Paste. Transpose rows and columns. (Windows
version only)
- Copy results or data to the Macintosh or Windows clipboard,
or export as a text file.
- Print graphs on any printer or export as Windows Metafile
(.WMF) or PICT (Mac) files.
- Annotate your data and analyses using a built-in notes editor.
- Notes are included in the data files.
- InStat files contain analysis choices as well as data so you can
quickly rerun the same test with multiple sets of data.
- Combine two columns (add, subtract, multiply, divide) to create
a new column. (Win only.)
- Import data from comma or tab delimited test files.
- Import indexed (stacked) data, entire tables or selected rows
and columns, filter selected data. (Windows only)
- Export the data table as a text table, or as indexed (stacked)
file. (Windows only)
- Exclude selected values. They appear on the data table, but are
treated as missing values by the analyses.
What InStat does not
do
InStat is not for everyone. It performs basic tests easily, but
does not handle advanced statistical tests. For example, InStat
does not perform two-way (or higher) ANOVA, logistic
regression, the Mantel-Haenszel test (to analyze a stack of
contingency tables), stepwise multiple regression, analyses of
survival curves, analysis of covariance, factor or cluster analysis,
polynomial regression or nonlinear regression. InStat is an ideal
tool for analyzing experimental data and data from small clinical
studies, but is not designed to analyze large clinical studies.
InStat has limited ability to select a subset of cases from a large
file and cannot cross-tabulate data to form a contingency
table.
System requirements:
Windows version -- 486 or better • Windows 3.1 or Windows
95/98 (or NT 4.x) • 4MB RAM • 3MB free on hard disk
Macintosh version -- System 6 or later • 700 KB RAM • and a
hard disk
All product descriptions and artwork are copyright 1995-2000 by GraphPad Software, Inc. All rights reserved.
GraphPad Prism, Prism and InStat are registered trademarks of GraphPad Software Inc.