A history teacher assigns letter grades on a test according to the following Per

Question

A history teacher assigns letter grades on a test according to the following Percentle scheme: A: Top 10% B. Scores below the top 10% and above the bottom 60% Scores below the top 40% and above the bottom 20% D Scores below the top 20% and above the bottom 10% F: Bottom 10% Scores on the test are normally distributed with a mean of 67 and a standard deviation of 132 Find the numerical limits for each letter grade Answer A Above 84 B Between 74 and 84 C. Between 56 and 73 D. Between 50 and 55 F Below 50 2.0 A Above 79 B Between 70 and 79 C Between 56 and 69 D Between 50 and 55 F Below 50 A Above 79 B Between 70 and 79 C: Between 56 and 69 D Between 52 and 55 F Below 52 A Above 84 B. Between 70 and 84 C Between 56 and 69 D Between 50 and 55 F Below 50

Explanation / Answer

Option 3 will be correct answer

A grade means that p-value of 0.90.

z score at 0.90 is 1.645

P(X< ?) = 0.90

From Z score table value for top 10% is Above 84.

B: Score below the top 10% and above the bottom 60%

value from

P(x<?)= 60

from z -score value the score will be 70.

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