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Scores on a recent exam followed a normal distribution and letter grades will be assigned with 15% A, 35% B, 30% C, 15% D, and 5% F. Suppose that Sue took the exam and had a standardized score of 0.85. What letter grade will Sue get?

Respuesta :

Using the normal distribution, it is found that Sue will get a letter grade of B.

In a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

  • It measures how many standard deviations the measure is from the mean.  
  • After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.

In this problem, Sue got a grade of 0.85, hence [tex]z = 0.85[/tex].

  • Looking at the z-table, z = 0.85 has a p-value of 0.8023, hence she is approximately in the top 20%, which is below the top 15% but above the top 50%, hence she got a letter grade of B.

A similar problem is given at https://brainly.com/question/25745464

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