1) Mean
The mean is given by the sum of the data divided by the number of data (4, in this case):

2) Standard deviation
The standard deviation is given by:

where

is the mean, that we already found at point 1), and N=4. Substituting data, we have:

Answer: 120
<u>Step-by-step explanation:</u>
Since the order of the numbers doesn't matter we can use the formula:

Answer:
a.) Commutative Property of addition
Step-by-step explanation:
Answer:
1.5
Step-by-step explanation:
12 / 8 = 1.5
Answer:

Step-by-step explanation:
If the population increases at a rate of 4% per annum, then:
In year 1:

Where
is the initial population and
is the population in year n
In year 2

It can also be written as:

Taking out common factor

Taking out common factor (1 + 0.04)

Taking out again common factor 
Simplifying

So

This is the equation that represents the population for year n
Then, in 4 years, the population will be:
