Question

Gail bought four snacks that cost $1.00, $1.50, $2.50, and $3.00. What is the average of the deviations from the mean?

Answer 1

The answer for this is 2

Answer 2

For this case we have that the average is given by:

μ = Σx/N

μ=
`\frac {1 + 1.50 + 2.50 + 3} {4}`

μ =
`\frac {8} {4}`

μ = 2

On the other hand, the deviation is given by:

σ = Root(Σ(x-μ)^2/N)

σ=
`\sqrt {\frac {(1-2) ^ 2 + (1.50-2) ^ 2 + (2.50-2) ^ 2 + (3-2) ^ 2)} {4}}`

σ =
`\sqrt {\frac {2.5} {4}}`

σ =
`\sqrt {0.625}`

σ = 0.790569415

ANswer:

μ = 2

σ= 0.790569415