Multiple choice

The mean deviation from the mean for the set of observations $-1,0,4$ is

  1. Less than $3$
  2. Less than $1$
  3. Greater than $2.5$
  4. Greater than $4.9$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mean = (-1 + 0 + 4) / 3 = 1. Deviations from mean: |-1 - 1| = 2, |0 - 1| = 1, |4 - 1| = 3. Mean deviation = (2 + 1 + 3) / 3 = 6 / 3 = 2. Since 2 is less than 3, option A is correct.

AI explanation

Using the method for mean deviation about the mean, first find the mean of the observations minus 1, 0 and 4. The mean is (minus 1 plus 0 plus 4) divided by 3, which is 1. The mean deviation is the average of the absolute deviations from this mean, calculated as (2 plus 1 plus 3) divided by 3, resulting in 2. This value is 2, which is less than 3.

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