Compare mean, median, mode, range
CONCEPTS
Tips
• Write out the equations for mean and range, and write out the sequence for mean and mode. The answer will be obvious after the information is there to see
PRACTICE PROBLEMS
Question 1 The list of numbers 41, 35, 30, X, Y, 15 has a median of 25 and the mode is 15. What is the mean?
-- Answer -- 26
The median is 25 => (30 + X) / 2 = 25. X = 20
The mode is 15 => Y = 15
The mean = (41 + 35 + 30 + 20 + 15 + 15)/6 = 26
Question 2 The mean of 5 integers is 52. The median of these 5 integers is 82. Three of the integers are 0, 12, and 82. Which of the following could be one of the other integers….52, 66, 84, 86, 105?
-- Answer -- 84
The sum of the other 2 integers is
5 * 52 – 0 – 12 – 82 = 166
52: The integers would be 0, 12, 52, 82, 114….82 is not the median
66: The integers would be 0, 12, 66, 82, 100…82 is not the median
84: The integers would be 0, 12, 82, 82, 84…82 is the median
86: The integers would be 0, 12, 80, 82, 86…82 is not the median
105: The integers would be 0, 12, 61, 82, 86, 105…82 is not the median
Question 3 What is the difference between the mean and median based on the histogram below.
-- Answer -- 0.9
Data Set = {1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 6, 7, 8}
Median = (3 + 4) / 2 = 3.5
Mean = (1 * 1 + 2 * 3 + 3 * 4 + 4 * 3 + 5 * 2 + 6 * 1 + 7 * 1 + 8 * 1) / 14 = 4.4
Difference = mean – median = 4.4 – 3.5 = 0.9
ACT PRACTICE PROBLEMS