Table to calculate the area under the Standard Normal Probability
Curve. |
Table to calculate the critical value for a chi-square distribution
with df degrees
of freedom and for an
significant level. |
Table to calculate the critical value for a Student’s
t-distribution with df degrees
of freedom and for an
significant level. |
Table to calculate the critical value for a Snedecor’s
F-distribution with df1 and
df2 degrees of freedom and for a 0.05 significant level. |
Spreadsheet to calculate critical values for standard normal,
normal, chi-squared, t- and F distributions.
|
EDUCATIONAL TOOLS FOR LEARNING STATISTICS IN BIOINFORMATICS
Statistical tables (pdf format) and spreadsheet (MS-excel
format) to calculate critical values of the more important statistical
distributions
Standard
normal distribution N(0,1)
Chi-square distribution
Student's
t-distribution
Snedecor's
F -distribution
MS-excel
spreadsheets of normal, chi-squared, t- and F- distributions
Considering n Bernoulli independent
variables X1,X2,…,Xn with
a probability of success p1=p2=…=pn,
the X random variable is defined
as equal to the number of successes in the n
trials and follows a binomial distribution.
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Considering n Bernoulli independent
variables X1,X2,…,Xn with a
probability of success p1=p2=…=pn,
the probability that the success on the mth
trials follows a geometric distribution.
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Considering n Bernoulli independent
variables X1,X2,…,Xn with
a probability of success p1=p2=…=pn,
the X random variable is defined
as equal to the number of successes until the mth
unsuccessful is observed and follows a negative geometric distribution.
|
A binomial distribution, with n large
and p small, can be approximated by
a Poission distribution with parameter
(the approach can be made when n>50
and p<0.1).
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Normal distribution with a mean
and standard deviation s.
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MS-Excel Spreadsheets for the graphical study of distribution
functions
Binomial
distribution
Geometric
distribution
Negative geometric distribution
Poisson
distribution
Normal
distribution
Exponential
distribution
MS-Excel spreadsheets for one-sample hypothesis tests
Conformity of the sample proportion with the population proportion.
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Conformity of the sample variance with the population variance.
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One-sample
hypothesis test for mean
One-sample
hypothesis test for proportion
One-sample
hypothesis test for variance
MS-Excel spreadsheet for the estimation of confidence intervals
Confidence
interval for proportion.
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Confidence intervals for variance.
Confidence intervals for variance ratios. ????
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Confidence
intervals for mean
Confidence
interval for proportion
Confidence
intervals for variances
Spreadsheets of MS-Excel two-sample hypothesis tests
Hypothesis test of two means from dependent samples that follow
a normal distribution, with d
unknown and n<=30.
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Test for variance.
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Two
sample hypothesis test for two independent means
Two
sample hypothesis test for two dependent means
Two
samples hypothesis test for two proportions
Two
sample hypothesis test for two variances
Spreadsheets for Bioinformatics statistical tests
Global Binomial test: the test is based on to count the number
of correct alignments between the two sequences. This variable
follows a binomial distribution that can be approached with
a normal distribution if the sequences are very large.
 |
Likelihood ratio: in many cases the null and alternative hypothesis
can be compared using a logarithm of the likelihood ratio. This
variable follows a binomial distribution that can be approached
with a normal distribution if the sequences are very large.
 |
A local success run test: this test is applied to compare two
sequences and is based on the length of the local success. The
statistic is defined as the maximum length of the well aligned
base fragments and follows a distribution of the maximum of
n geometric distributions.
|
BLAST Basic Local Alignment Search Tool (Altschul, S.F., Gish
W., Miller W., Myers E.W., and Lipman D.J. J. Mol. Biol. 1990:
215:403-10) is an algorithm used to study nucleic acid sequence
alignments and the predicted maximum length of the well-aligned
segment is used.
|
BLAST Basic Local Alignment Search Tool (Altschul, S.F., Gish
W., Miller W., Myers E.W., and Lipman D.J. J. Mol. Biol. 1990:
215:403-10) is an algorithm used to study protein sequence and
the predicted maximum length of the well-aligned segment is
used.
|
Global
Binomial test and it's aproximation by normal distribution
Likelihood
ratio - binomial distribution and it's aproximation by normal distribution
Local
sucess run test
BLAST:
Nucleotide sequence comparisons
BLAST:
Protein sequences comparisons
Links
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