Update index.html

fixing typos

Author: sally-martinez

index.html

@@ -1192,7 +1192,7 @@ <h1>Activity for Rockwern Elementary School Students Science Day</h1>
       A major goal of scientific research is to be accurate and reproducible. Through this activity, students will learn important context relating to accuracy and reproducibility of scientific research, such as the concepts of estimation, repeated surveys, and more.  
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     <p>
-      <strong>Materials</strong> - <a href="https://github.com/zipkinlab/Penguin-Challenge">Link to materials</a>
+      <strong>Materials</strong> - <a href="https://github.com/zipkinlab/PenguinChallenge">Link to materials</a>
       <br>
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