Fix display of percent signs for hardcopies in 2 statistics problems

% -> $PERCENT

Author: d-torrance

Contrib/Piedmont/StevensStatistics/3-StatisticalTablesAndGraphics/3.1.1.pg

@@ -112,7 +112,7 @@ $PAR
     for ($i = 0; $i < 6; $i ++) {
         $rel_table_row[$i] = [
             $lower_class_limit[$i] . ' - ' . $upper_class_limit[$i],
-            ans_rule(4) . '%'];    
+            ans_rule(4) . '$PERCENT'];
     }
 
 DataTable(
@@ -133,7 +133,7 @@ $PAR
     for ($i = 0; $i < 6; $i ++) {
         $cum_table_row[$i] = [
             'less than ' . $class_boundary[$i],
-            ans_rule(4), ans_rule(4) . '%'];    
+            ans_rule(4), ans_rule(4) . '$PERCENT'];
     }
 
 DataTable(

Contrib/Piedmont/StevensStatistics/3-StatisticalTablesAndGraphics/3.1.2.pg

@@ -116,7 +116,7 @@ $PAR
     for ($i = 0; $i < 10; $i ++) {
         $rel_table_row[$i] = [
             $lower_class_limit[$i] . ' - ' . $upper_class_limit[$i],
-            ans_rule(4) . '%'];    
+            ans_rule(4) . '$PERCENT'];
     }
 
 DataTable(
@@ -137,7 +137,7 @@ $PAR
     for ($i = 0; $i < 10; $i ++) {
         $cum_table_row[$i] = [
             'less than ' . $class_boundary[$i],
-            ans_rule(4), ans_rule(4) . '%'];    
+            ans_rule(4), ans_rule(4) . '$PERCENT'];
     }
 
 DataTable(