math
posted by chris .
Mary's test grades were 81, 89, 86, 86, and 84. Mary's teacher recorded one of her grades incorrectly. Instead of an 89, Mary's second test score should have been a 55. Which measure(s) of central tendency are affected by this change?

Mode will still be 86, but mean and median will be changed. Mean functions very much like a fulcrum (balance point). Going from highest score to lowest will change the median (50th percentile).

Mary's test grades were 73, 86, 89, 84, and 86. Mary's teacher recorded one of her grades incorrectly. Instead of an 86, Mary's second test score should have been an 84. Which measure(s) of central tendency are affected by this change?