A History Teacher Assigns Letter Grades on a Test According

question 109

Multiple Choice

A history teacher assigns letter grades on a test according to the following scheme:
A: Top 10%
B: Scores below the top 10% and above the bottom 60%
C: Scores below the top 40% and above the bottom 20%
D: Scores below the top 80% and above the bottom 10%
F: Bottom 10%
Scores on the test are normally distributed with a mean of 65 and a standard deviation of 13.9. Find the numerical limits for each letter grade.

• A) A: Above 78
• B: Between 68 and 78
• C: Between 54 and 67
• D: Between 50 and 53
• F: Below 50
• B) A: Above 83
• B: Between 68 and 83
• C: Between 53 and 67
• D: Between 47 and 52
• FBelow 47
• C) A: Above 83
• B: Between 72 and 83
• C: Between 53 and 71
• D: Between 47 and 52
• F: Below 47
• D) A: Above 78
• B: Between 68 and 78
• C : Between 54 and 67
• D: Between 47 and 53
• F: Below 47

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