The formula to calculate the variance of a sample is:

$\text{Variance} = (\text{Standard Deviation})^2$

Given that the standard deviation is 11.9197 kg, we can calculate the variance by squaring the standard deviation.

$\text{Variance} = (11.9197)^2 = 142.0909 \, \text{kg}^2$

Thus, the variance of their weights is:

$142.0909 \, \text{kg}^2$

(Rounded to four decimal places as needed.)

Would you like more details or have any questions?

Here are some related questions:

1. What is the relationship between variance and standard deviation?
2. How do you calculate the sample variance for larger data sets?
3. Why is the unit of variance the square of the unit of the data (e.g., kg²)?
4. How is the variance of a population different from the variance of a sample?
5. What is the significance of rounding in statistical calculations?

Tip: Always double-check the rounding rules and ensure that you maintain the correct number of decimal places as requested.