Find the absolute mean deviation of the sample 10, 12, 14, 11, 13.

Analyze the question: We need the mean absolute deviation: the average distance of each value from the mean.

Concept: Mean absolute deviation = Σ|x − x̄| / n

Solution:

Step 1: Find the mean. x̄ = (10 + 12 + 14 + 11 + 13) / 5 = 60 / 5 = 12

Step 2: Find the absolute deviations from the mean.

• |10 − 12| = 2
• |12 − 12| = 0
• |14 − 12| = 2
• |11 − 12| = 1
• |13 − 12| = 1

Step 3: Sum the deviations. 2 + 0 + 2 + 1 + 1 = 6

Step 4: Divide by n. Mean deviation = 6 / 5 = 1.2

Answer: The result is 1.2, which is option E.

Tip: Never confuse the mean (12, option C) with the mean deviation. Also remember that the deviations from the mean without absolute values would add up to zero, so you must take absolute values. The deviations of 5 numbers here are small, so the answer should be a small number like 1.2, and this lets you quickly rule out options like 14.6 or 6.2.