Question

The grades of a science test are normally distributed. Thanh finds that his grade on the test has a z-score of 3.5. Which statement must be true?

Thanh’s grade is 3.5 standard deviations above the mean of the test grades.

Thanh’s grade is 3.5 standard deviations below the mean of the test grades.

Thanh’s grade is 3.5 points below the mean of the test grades.

Thanh’s grade is 3.5 points above the mean of the test grades.

Answer 1

Answer:

Option A

Step-by-step explanation:

Among the four options given in question statement, the correct answer is Thanh's grade is 3.5 standard deviations below the mean of the test grades.

Z score represents the standard deviation. The positive and negative signs indicate how much above or below the score is with respect to standard deviation. Very high or very low scores are at the extreme ends of the normal distribution curve