From c71e2b5042e627610f262d7a748e9eec6d0dd67b Mon Sep 17 00:00:00 2001
From: Roberto B <roberto.butti@gmail.com>
Date: Mon, 21 Feb 2022 20:52:09 +0100
Subject: [PATCH] Update README.md

---
 README.md | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index 24ed906..1d091aa 100644
--- a/README.md
+++ b/README.md
@@ -38,12 +38,14 @@ Stat class has methods to calculate an average or typical value from a populatio
 - quantiles(): cut points dividing the range of a probability distribution into continuous intervals with equal probabilities;
 - thirdQuartile(): 3rd quartile, is the value at which 75 percent of the data is below it;
 - firstQuartile(): first quartile, is the value at which 25 percent of the data is below it;
-- pstdev(): Population standard deviation
-- stdev(): Sample standard deviation
-- pvariance(): variance for a population
-- variance(): variance for a sample
-- geometricMean(): geometric mean
-- harmonicMean(): harmonic mean
+- pstdev(): Population standard deviation;
+- stdev(): Sample standard deviation;
+- pvariance(): variance for a population;
+- variance(): variance for a sample;
+- geometricMean(): geometric mean;
+- harmonicMean(): harmonic mean;
+- correlation(): the Pearson’s correlation coefficient for two inputs;
+- covariance(): the sample covariance of two inputs.
 
 #### Stat::mean( array $data )
 Return the sample arithmetic mean of the array _$data_.