**Fsdb::Filter::dbcolstats - compute statistics on a fsdb column**

Compute statistics over a COLUMN of data. Records containing non-numeric data are considered null do not contribute to the stats (with the "-a" option they are treated as zeros). Confidence intervals are a t-test (+/- (t_{a/2})*s/sqrt(n)) and assume ...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbmultistats - run dbcolstats over each group of inputs identified by some key**

The input table is grouped by KeyField, then we compute a separate set of column statistics on ValueField for each group with a unique key. Assumptions and requirements are the same as dbmapreduce (this program is just a wrapper around that program):...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbrowcount - count the number of rows in an Fsdb stream**

Count the number of rows and write out a new fsdb file with one column (n) and one value: the number of rows. This program is a strict subset of dbcolstats. Although there are other ways to get a count of rows ("dbcolstats", or "dbrowaccumulate -C 1"...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbpipeline - allow db commands to be assembled as pipelines in Perl**

This module makes it easy to create pipelines in Perl using separate processes. (In the past we used to use perl threads.) By default (as with all Fsdb modules), input is from STDIN and output to STDOUT. Two helper functions, fromfile and tofile can ...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbcolhisto - compute a histogram over a column of Fsdb data**

This program computes a histogram over a column of data. Records containing non-numeric data are considered null do not contribute to the stats (optionally they are treated as zeros). Defaults to 10 buckets over the exact range of data. Up to three p...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbmapreduce - reduce all input rows with the same key**

Group input data by KeyField, then apply a function (the "reducer") to each group. The reduce function can be an external program given by ReduceCommand and ReduceArguments, or an Perl subroutine given in CodeFile or FilterCode. If a "--" appears bef...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbrvstatdiff - evaluate statistical differences between two random variables**

Produce statistics on the difference of sets of random variables. If a hypothesized difference is given (with "-h"), to does a Student's t-test. Random variables are specified by: "m1c", "m2c" The column names of means of random variables. "sd1c", "s...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbcolscorrelate - find the coefficient of correlation over columns**

Compute the coefficient of correlation over two (or more) columns. The output is one line of correlations. With exactly two columns, a new column *correlation* is created. With more than two columns, correlations are computed for each pairwise combin...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbcolstatscores - compute z-scores or t-scores for each value in a population**

Compute statistics (z-score and optionally t-score) over a COLUMN of numbers. Creates new columns called "zscore", "tscore". T-scores are only computed if requested with the "-t" option, or if "--tmean" or "--tstddev" are explicitly specified (defaul...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbcolmovingstats - compute moving statistics over a window of a column of data**

Compute moving statistics over a COLUMN of data. Records containing non-numeric data are considered null do not contribute to the stats (optionally they are treated as zeros with "-a"). Currently we compute mean and sample standard deviation. (Note w...

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT**Fsdb::Filter::dbcolsregression - compute linear regression between two columns**

Compute linear regression over "column1" and "column2". Outputs slope, intercept, and correlation coefficient....

JOHNH/Fsdb-2.68 - 19 Sep 2019 15:23:50 GMT