Add CHANGES.txt entry; a little more copy editing
diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 7c8a26f..819b7eb 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -352,6 +352,8 @@
* SOLR-15010: Thread dump using jattach if available and jstack is missing. (Eric Pugh)
+* SOLR-13105: Add Visual Guide to Math Expressions to the Ref Guide (Joel Bernstein, Cassandra Targett)
+
================== 8.7.0 ==================
Consult the lucene/CHANGES.txt file for additional, low level, changes in this release.
diff --git a/solr/solr-ref-guide/src/statistics.adoc b/solr/solr-ref-guide/src/statistics.adoc
index 759d995..7bee9cc 100644
--- a/solr/solr-ref-guide/src/statistics.adoc
+++ b/solr/solr-ref-guide/src/statistics.adoc
@@ -404,7 +404,7 @@
In the example below a random sample containing two fields, `filesize_d` and `response_d`, is drawn from
the logs collection using the `random` function. The fields are vectorized into the
-variables *x* and *y* and then *Spearman's* correlation for
+variables `x` and `y` and then *Spearman's* correlation for
the two vectors is calculated using the `corr` function.
image::images/math-expressions/correlation.png[]
@@ -439,7 +439,7 @@
image::images/math-expressions/corrmatrix.png[]
Notice in the example the correlation matrix is square with complaint types shown on both
-the *x* and y-axises. The color of the cells in the heat map shows the
+the x- and y-axes. The color of the cells in the heat map shows the
intensity of the correlation between the complaint types.
The heat map is interactive, so mousing over one of the cells pops up the values
@@ -458,7 +458,7 @@
In the example below a random sample containing two fields, `filesize_d` and `response_d`, is drawn from
the logs collection using the `random` function. The fields are vectorized into the
-variables *x* and *y* and then the covariance for
+variables `x` and `y` and then the covariance for
the two vectors is calculated using the `cov` function.
image::images/math-expressions/covariance.png[]
