.htaccess is per directory context vs putting it in the config file so your pattern is not matching.
From the documentation:
When using the rewrite engine in .htaccess files the per-directory
prefix (which always is the same for a specific directory) is
automatically removed for the RewriteRule pattern matching and
automatically added after any relative (not starting with a slash or
protocol name) substitution encounters the end of a rule set. See the
RewriteBase directive for more information regarding what prefix will
be added back to relative substitutions.
The removed prefix always ends with a slash, meaning the matching
occurs against a string which never has a leading slash. Therefore,
a Pattern with ^/ never matches in per-directory context.
So your rules should look like this without the leading / in the RewriteRule.
RewriteEngine On
RewriteCond %{QUERY_STRING} ^id=275$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^about_news_info.aspx http://examplepage.com/news-events/test1 [L,R=301]
RewriteCond %{QUERY_STRING} ^cateid=373$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^about_news.aspx http://examplepage.com/news-events/test2 [L,R=301]
Without checking for query string which really isn't needed.
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^about_news_info.aspx$ http://examplepage.com/news-events/test1? [L,R=301]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^about_news.aspx$ http://examplepage.com/news-events/test2? [L,R=301]