KatellaFunny
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Help me please !

Scores on a statewide standardized test are normally distributed with a mean of 12.89 and a standard deviation of 1.95. Certificates are given to students whose scores are in the top 2% of those who took the test. This means that they scored better than 98% of the other test takers. Marcus received his score of 13.7 on the exam and is wondering why he didn’t receive a certificate. Show all work to determine whether Marcus’ score was high enough to earn a certificate. Write a letter to Marcus explaining whether or not he will be receiving a certificate. Include a brief summary of your statistical analysis in your letter.

Respuesta :

Marcus score is 13.7, the mean is 12.89, and the standard deviation is 1.95, so I’ll do ( 13.7 – 12.89)/ 1.95, Since Marcus' z-score is 0.415. The area to the left of the z-score is 65.9% so therefore Marcus did scored better than 65.9% of the students. So Marcus needs to score 98% better of all the other students in order for him to receive an actual certificate.
you take the mean of 12.89 from marcus' score od 13.7  to get .81, then divide that by the standard deviation of 1.95. This gives you .415 and thats 65.9% on the z table. In the summary tell him he only scored better than 65.9% of students or average.