Question

A teacher gave a 25 question multiple choice test. After scoring the tests, she computed a mean and standard deviation of the scores. The standard deviation was 0. Based on this information........

A. None of the above.
B. she must have made a mistake.
C. about half the scores were above the mean.
D. all the students had the same score.

Answer 1

The correct answer is D. all the students had the same score because a standard deviation of 0 indicates no variability in the test scores, meaning every student received the same score.

Step-by-step explanation:

If a teacher gives a test with a standard deviation of 0, it means that all the students received the same score on the test. Standard deviation is a measure of how spread out the numbers are in a data set. If all the students scored differently, there would be some degree of spread, and the standard deviation would be greater than 0. However, if every student had identical scores, there would be no spread at all, hence a standard deviation of 0. So, the correct answer to the question is D. all the students had the same score.