the grades of a science test are normally distributed. thanh finds that his grade on the test has a z…

the grades of a science test are normally distributed. thanh finds that his grade on the test has a z - score of - 2.5. which statement must be true?\no thanhs grade is 2.5 standard deviations below the mean of the test grades.\no thanhs grade is 2.5 points below the mean of the test grades.\no thanhs grade is 2.5 standard deviations above the mean of the test grades.\no thanhs grade is 2.5 points above the mean of the test grades.

the grades of a science test are normally distributed. thanh finds that his grade on the test has a z - score of - 2.5. which statement must be true?\no thanhs grade is 2.5 standard deviations below the mean of the test grades.\no thanhs grade is 2.5 points below the mean of the test grades.\no thanhs grade is 2.5 standard deviations above the mean of the test grades.\no thanhs grade is 2.5 points above the mean of the test grades.

Answer

Brief Explanations:

The z - score represents the number of standard deviations a data - point is from the mean. A negative z - score indicates that the data - point is below the mean. Since Thanh's z - score is - 2.5, it means his grade is 2.5 standard deviations below the mean.

Answer:

Thanh's grade is 2.5 standard deviations below the mean of the test grades.