| #------------------------------------------------------------- |
| # |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you under the Apache License, Version 2.0 (the |
| # "License"); you may not use this file except in compliance |
| # with the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, |
| # software distributed under the License is distributed on an |
| # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| # KIND, either express or implied. See the License for the |
| # specific language governing permissions and limitations |
| # under the License. |
| # |
| #------------------------------------------------------------- |
| |
| |
| posSamples = read($1, format="text") |
| negSamples = read($2, format="text") |
| |
| #computing sample sizes |
| posSampleSize = nrow(posSamples) |
| negSampleSize = nrow(negSamples) |
| |
| #computing means |
| posSampleMeans = colMeans(posSamples) |
| negSampleMeans = colMeans(negSamples) |
| |
| #computing (unbiased) variances |
| posSampleVariances = (colSums(posSamples^2) - posSampleSize * posSampleMeans^2) / (posSampleSize-1) |
| negSampleVariances = (colSums(negSamples^2) - negSampleSize * negSampleMeans^2) / (negSampleSize-1) |
| |
| #computing t-statistics and degrees of freedom |
| t_statistics = (posSampleMeans - negSampleMeans) / sqrt(posSampleVariances/posSampleSize + negSampleVariances/negSampleSize) |
| degrees_of_freedom = round(((posSampleVariances/posSampleSize + negSampleVariances/negSampleSize) ^ 2) / (posSampleVariances^2/(posSampleSize^2 * (posSampleSize-1)) + negSampleVariances^2/(negSampleSize^2 * (negSampleSize-1)))) |
| |
| write(t_statistics, $3, format="text") |
| write(degrees_of_freedom, $4, format="text") |
