Question

At what time can a grade 2 interval be extended to a grade 3.?

Answer 1

A grade 2 interval can be extended to a grade 3 when the number of students in that interval reaches or exceeds 6. The earliest time a grade 2 interval can be extended to a grade 3 is the interval from 74.5-80.5.

Step-by-step explanation:

A grade 2 interval can be extended to a grade 3 when the number of students in that interval reaches or exceeds the minimum number of students required for a grade 3. Looking at the provided data, we can see that the grade intervals have a width of 6, so the minimum number of students required for a grade 3 would be 6. Let's analyze the intervals:

1. A grade 2 interval with 50-56.5 would need at least 5 more students to reach 6, so it cannot be extended to a grade 3 yet.
2. A grade 2 interval with 56.5-62.5 would need at least 4 more students to reach 6, so it cannot be extended to a grade 3 yet.
3. A grade 2 interval with 62.5-68.5 would need at least 3 more students to reach 6, so it cannot be extended to a grade 3 yet.
4. A grade 2 interval with 68.5-74.5 would need at least 2 more students to reach 6, so it cannot be extended to a grade 3 yet.
5. A grade 2 interval with 74.5-80.5 would need at least 1 more student to reach 6, so it can be extended to a grade 3.
6. A grade 2 interval with 80.5-86.5 already has 6 students, so it can be considered a grade 3 interval.
7. A grade 2 interval with 86.5-92.5 already has 6 students, so it can be considered a grade 3 interval.
8. A grade 2 interval with 92.5-98.5 already has 6 students, so it can be considered a grade 3 interval.

So, the earliest time a grade 2 interval can be extended to a grade 3 is the interval from 74.5-80.5.