To calculate the relative frequency for the third class (260 - 279), you need to divide the frequency of that class by the total number of students, and then multiply by 100 to express it as a percentage.

The frequency for the 260 - 279 class is 6, and the total number of students is 50.

$\text{Relative frequency} = \left( \frac{\text{Frequency of class}}{\text{Total frequency}} \right) \times 100$

$\text{Relative frequency} = \left( \frac{6}{50} \right) \times 100 = 12$

So, the relative frequency for the 260 - 279 class is 12.

Would you like further details on this, or have any additional questions?

Here are 5 related questions:

1. How do you calculate relative frequency for the entire data set?
2. What is the cumulative frequency for all the classes up to 260 - 279?
3. How can relative frequency help in comparing two data sets?
4. Can you build a cumulative relative frequency distribution from this data?
5. What is the relative frequency for the highest class (300 - 319)?

Tip: When working with frequency distributions, relative frequency is helpful for comparing different sets of data without being affected by the overall sample size.