To find the modal class (nilai modus) from the grouped data provided in the image, we need to identify the class interval with the highest frequency.

Here is the provided dataTo find the modal class (nilai modus) from the grouped data provided in the image, we need to identify the class interval with the highest frequency.

Here is the provided

Step-by-Step Solution:

1. Identify the modal class: The class with the highest frequency is 66 - 72 with a frequency of 9. This is the modal class.

2. Formula for calculating the mode in grouped data: $\text{Mode} = L + \left( \frac{f_m - f_{1}}{2f_m - f_{1} - f_{2}} \right) \times h$ Where:

   • $L$ = lower boundary of the modal class = 66
   • $f_m$ = frequency of the modal class = 9
   • $f_{1}$ = frequency of the class preceding the modal class = 8
   • $f_{2}$ = frequency of the class succeeding the modal class = 5
   • $h$ = class width (difference between upper and lower boundaries of a class) = $72 - 66 = 6$

3. Substitute the values into the formula: $\text{Mode} = 66 + \left( \frac{9 - 8}{2(9) - 8 - 5} \right) \times 6$ $\text{Mode} = 66 + \left( \frac{1}{18 - 8 - 5} \right) \times 6$ $\text{Mode} = 66 + \left( \frac{1}{5} \right) \times 6$ $\text{Mode} = 66 + 1.2 = 67.2$

Conclusion:

The mode of the data is 67.2.

Do you want further details or have any questions about this? Here are 5 follow-up questions for practice:

1. What is the difference between mode and mean in statistics?
2. How would you compute the median for this grouped data?
3. Can there be more than one modal class in a data set?
4. How does the class width affect the calculation of mode?
5. How would the mode change if one of the frequencies increased?

Tip: Always ensure the data is organized clearly when calculating descriptive statistics to avoid confusion.