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CONSULTANCY LINKS
Choosing the Right Tests
Calculators, Plotters, Function
Integrators, and Interactive Programming Environments
Probability Distribution Functions:
Tables, Graphs, Random Number Generators
Compute probabilities for the four
most common probability distributions
- Normal,
t, Chi-Square, and Binomial (density and cumulative) probabilities
- Central
and tail areas for Normal, Student, F, Chi-Square, Binomial, and
Poisson distributions
- Statistical
probability distribution functions: Normal, Student t, Chi-Square,
Fisher F
- Reverse
computations
Compute probabilities for a specific
distributions
- Normal
distribution areas, with nice graphical interpretations
- A
very attractive page for Normal distribution (and inverse), with
detailed explanations
- Normal
area (1-tailed)
- Chi-Square
probabilities, and reverse, with a detailed explanation
- Chi
Square probabilities and reverse
- Chi-Square
Distribution
- Chi-Square
Distribution
- Student
t Distribution
- Studentized
Range
- Probabilities
for the Fisher F distribution
- Binomial
probability calculator
- Binomial
Approximation of the Normal Distribution
- Cumulative
frequency for the Binomial distribution
- Probabilities
for Gamma, complete Beta, and Incomplete Beta distributions
- Multinomial
DistributionNormal
Curve
- Critical Values for: Student
t, Fisher
F, Studentized
Range Statistic and Dunnett's Test, Chi-Square,
Binomial
Test, Wilcoxon
Ranked-Sums Test, Wilcoxon
Signed Ranks Test, and
Correlation
Coefficient
- Converting
r to Z
- Statistical Power of:
Z
Test, t-Test
for One Sample or Two Related Samples, t-Test
for Two Independent Samples, Analysis
of Variance, and
Correlation
Coefficient
- Required
Sample Size for various tests
Random Number Generators
Confidence Intervals, Single-Population
Tests, Measurement Errors
- Confidence Intervals...
- Single-Population Tests...
- Test
a sample proportion against a postulated population proportion
- Mean,
SD, confidence interval, etc. for a set of values
- Student
t-test of a single mean (vs specified value) from N, mean, SD
- Another
Student t-test of a single mean (vs specified value) from N,
mean, SD
- Similar
test of single mean vs 0 (equivalent to a paired Student t) from
N, mean, SD
- Test
observed vs. expected rates of occurrence of events
- Similar
to above, but used to study the distribution of accidents and
events at the individual level
- Exact
confidence intervals around a rate-ratio
- Test
observed vs expected proportions
- Binomial
Test
- Chi-Square "Goodness of Fit"
test for observed vs expected counts
- Measurement Errors and Error
Propagation...
Sample Comparisons: t-Tests, ANOVAs,
Non-parametric Comparisons
- Student t-test (for comparing two
samples)...
- a
very general Student t-test web page
- t-test,
paired
or unpaired
- t-test, paired
or unpaired
- t-test, paired
or unpaired
- t-test,
paired
- t-test,
unpaired (tests for equality of variances, and performs both the
equal-variance and unequal-variance t-test)
- t-test, Unpaired
- A general
2-sample comparison calculator, for paired, unpaired,
equal-variance
- Unpaired
t-test from summary data (N, mean, SD)
- Very
general t-test program for comparing measured quantities,
observed counts, and proportions between two unpaired samples
- Test
differences between two observed proportions
- ANOVA (Analysis of Variance)
- Non-parametric tests (use these when
the data is not normally distributed)...
- Comparison of proportions between two
groups...
- Sequential Analysis
Contingency Tables, Cross-tabs,
Chi-Square Tests
Regression, Correlation, Least Squares
Curve-fitting, Non-parametric Correlation
Analysis of Survival Data
Bayesian Methods
Other Statistical Tests and Analyses
Specialized and Discipline-Specific
Tests and Analyses
Martindale's
Reference Desk - Calculators On-Line - Statistics
- Biostatistical Calculators...
- Number
Needed to Treat
- Number
Needed to Treat
- Clinical
Significance Calculator
- Thorough
analysis of 2-by-2 table relevant to Predictions and Diagnostic
Tests
- Calculation
of posttest probability from Likelihood Ratio and pretest
probability
- Conversion
of Sensitivity and Specificity to Likelihood Ratios
- Calculator
to predict the probability of a successful outcome to lumbar
disc surgery
- LODS
- Logistic Organ Dysfunction System calculator
- APACHE-II
Score for acute physiology and chronic
health evaluation
- Calculators
for Clinical Formulas -- A-a
Gradient, Anion
Gap, Body
Surface Area, Body Mass Index, Estimated
Creatinine Clearance, Fractional
Excretion of Sodium, Heart
Disease Risk, Ingested
Substance Blood Level, Pregnancy
Due Date , Serum
Osmolality , and Weights
and Measures (converts lbs. to kgs. and F to C)
- Disparate
Impact Analysis
- Item
Analysis -- for multiple choice
questionnaires
- Investment
Derivative Calculations
Power, Sample Size and Experimental
Design Calculations
- Comparing
a mean to a specified value
(also available at
another website)
- Power
or sample
size for one-group comparison, when you can assume that the
values come from a normal distribution.
- Comparing
a proportion to a specified value
- Comparing
a proportion to a specified value
(also available at
another website)
- Sample
size needed for a given confidence and a given maximum allowable
deviation, for means, proportions, and totals
- Comparing
on observed number of occurrences to a specified rate of occurrence
- Sample
size and 95% confidence interval for a
variable, knowing the population standard deviation
- Another
sample-size / confidence interval calculator for proportions in
finite samples
- Difference between two proportions...
- Difference
between two rates of occurrence of events
- Survival
outcome analysis
- Sample
size needed for comparison of 2 or more groups
- Sample
size computation for multiple comparisons
SOFTWARE
PC-Size:
Consultant (sample size calculations)
Logistic
regression for Epi Info
Logistic
regression for SYSTAT (includes ASCII to SYSTAT conversion
program)
Miscellaneous
statistical procedures for SYSTAT (normality, unimodality,
two-phase regression, Johnson-Neyman ANCOVA, Alternating Conditional
Expectations, incomplete paired data, dependent correlations, ...)
Exact
randomization tests for SYSTAT (includes ASCII to SYSTAT
conversion program)
The
Statistician's Swiss Army Knife (probability distributions
(normal, t, chi-square, F, binomial, Poisson, studentized range)
PCT--the
routine SYSTAT forgot--for calculating distribution percentiles.
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