The following ten scores were obtained on a 20-point quiz: 4, 5, 8, 9, 11, 13, 15, 18, 18, and 20. The teacher computed the usual descriptive measures of center (central tendency) and variability (dispersion) for these data, and then discovered an error was made. One of the 18's should have been a 16. Which one of the following measures, calculated on the corrected data, would change from the original computation?
A) mean and standard deviation
B) mean and median
C) range and median
D) mean and range.
E) mean, standard deviation, range and median

Question

Quizplus · Accepted Answer

The mean and standard deviation would be affected by changing one of the scores from an 18 to a 16. The median and range would remain the same because only one score is being changed, and neither of these measures is affected by extreme scores at one end of the distribution. Therefore, the correct answer is A) mean and standard deviation.

The Following Ten Scores Were Obtained on a 20-Point Quiz