Question

Omar recorded the number of hours he worked each week for a year. Below is a random sample that he took from

data.
13, 17, 9, 21
What is the standard deviation for the data?

Answer 1

Approx. 4.47

Explanation:

To calculate the standard deviation for the data, we need to follow these steps:

1. Calculate the mean (average) of the data:

mean = (13 + 17 + 9 + 21) / 4 = 15

2. Calculate the difference between each data point and the mean:

13 - 15 = -2

17 - 15 = 2

9 - 15 = -6

21 - 15 = 6

3. Square each difference:

(-2)^2 = 4

2^2 = 4

(-6)^2 = 36

6^2 = 36

4. Calculate the variance by taking the average of the squared differences:

variance = (4 + 4 + 36 + 36) / 4 = 20

5. Calculate the standard deviation by taking the square root of the variance:

standard deviation = sqrt(variance) = sqrt(20) ≈ 4.47

Therefore, the standard deviation for the data is approximately 4.47.