Find the best solutions to your problems with the help of IDNLearn.com's experts. Our community is here to provide the comprehensive and accurate answers you need to make informed decisions.

The weekly salaries of a sample of employees at the local bank are given in the table below:

| Employee | Weekly Salary |
|----------|----------------|
| Anja | [tex]$245 |
| Raz | $[/tex]300 |
| Natalie | [tex]$325 |
| Mic | $[/tex]465 |
| Paul | $100 |

What is the variance for the data?

[tex]\[ \text{Variance: } s^2 = \frac{(x_1 - \bar{x})^2 + (x_2 - \bar{x})^2 + \ldots + (x_n - \bar{x})^2}{n - 1} \][/tex]

A. 118.35

B. 132.32


Sagot :

To calculate the variance of the weekly salaries of the employees, we follow these steps:

### Step 1: List the salaries and calculate the mean
First, we list the salaries given:
- \[tex]$245 - \$[/tex]300
- \[tex]$325 - \$[/tex]465
- \$100

To find the mean salary ([tex]\(\bar{x}\)[/tex]), sum up the salaries and divide by the number of employees.

[tex]\[ \bar{x} = \frac{245 + 300 + 325 + 465 + 100}{5} \][/tex]

[tex]\[ \bar{x} = \frac{1435}{5} = 287 \][/tex]

### Step 2: Calculate the squared differences from the mean
Next, we subtract the mean salary from each individual salary and square the result.

[tex]\[ (245 - 287)^2 = (-42)^2 = 1764 \][/tex]
[tex]\[ (300 - 287)^2 = (13)^2 = 169 \][/tex]
[tex]\[ (325 - 287)^2 = (38)^2 = 1444 \][/tex]
[tex]\[ (465 - 287)^2 = (178)^2 = 31684 \][/tex]
[tex]\[ (100 - 287)^2 = (-187)^2 = 34969 \][/tex]

### Step 3: Sum the squared differences
Now, we sum all these squared differences:

[tex]\[ 1764 + 169 + 1444 + 31684 + 34969 = 70030 \][/tex]

### Step 4: Divide by the number of observations minus one (n-1) to get the sample variance
Since we have a sample size of 5 (n = 5), we divide by 4 (n-1):

[tex]\[ s^2 = \frac{70030}{5-1} = \frac{70030}{4} = 17507.5 \][/tex]

So, the sample variance [tex]\(s^2\)[/tex] is 17507.5.