Question

Annual entertainment expenses in a population of 100 families have a mean of $2040 and a standard deviation of $360.

(a) Find the mean and standard deviation of monthly expenses.
(b) What is the total amount of monthly entertainment expenses for this population?

Answer 1

The correct answer is:

(a) Mean = 170,

Standard deviation = 30

(b) 1700

Explanation:

Given:

• n = 100
• μ = 2040
• σ = 360

(a)

Mean of monthly expenses will be:

=
`(\mu)/(2)`

=
`(2040)/(2)`

=
`170`

Standard deviation will be:

=
`(\sigma)/(12)`

=
`(360)/(12)`

=
`30`

(b)

The total amount of monthly expenses will be:

=
`n* (\mu)/(12)`

=
`100* 170`

=
`1700`