The formular (N + 1)/2 is used to determine the

Analyze the question: The formula (N + 1)/2 is a statistical formula. We need to decide which measure it gives.

Explain the concept:

• Mean = ΣX / N (sum of values divided by number of values)
• Median = the middle value of an ordered data set. Its position is found using (N + 1)/2
• Mode = the most frequently occurring value (no formula needed, you just count)
• Standard deviation = √[Σ(x − x̄)² / N]
• Mean deviation = Σ|x − x̄| / N

Step-by-step solution:

1. Arrange the data in ascending (or descending) order.
2. Count the number of items, N.
3. Find the position of the middle item using (N + 1)/2.

Example: For the data 2, 4, 6, 8, 10, we have N = 5. Position = (5 + 1)/2 = 3rd item, which is 6. That is the median.

If N is even, e.g. 2, 4, 6, 8 with N = 4, the position is (4 + 1)/2 = 2.5. This means the median is the average of the 2nd and 3rd items: (4 + 6)/2 = 5.

Answer: The formula (N + 1)/2 is used to locate the median, which is option B.

Exam tip: Remember "Median = Middle". Whenever you see (N + 1)/2, think of the position of the middle item. Mean uses ΣX/N, so don't confuse the two!