Students struggled with…

  • Finding a value from a given area.  They used the given area as a z-score and found the corresponding proportion in table A.
  • Questions that had two parts.  For example, calculate and interpret the z-score.  They simply forgot to answer the second part.
  • Using specific language. For example, “It is normal because it is linear.”


  • Students have struggled with finding a value from an area every year.  Make sure to stress that students draw a picture of the situation on a Normal curve.  This helps them to catch their mistake.  If many students continue to struggle, try to have students begin each problem by identifying what the question is asking for, a value or an area.
  • It’s really important that students overcome this error as answering a question completely is key for the AP test.  Have students box in or underline the question in the problem.  After they finish their work, they should refer back to the question and make sure they’ve answered all parts.
  • Precise language is very important.  We tell students to avoid the word “it” whenever possible.  Additionally, students should always say “approximately Normal” as nothing in context is perfectly Normal.


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