Question

what is the median? 90 81 86 70 78 81 82 79 81

Explanation:

Step1: Order the data set

First, we need to arrange the given numbers in ascending order. The numbers are 90, 81, 86, 70, 78, 81, 82, 79, 81. Arranging them from smallest to largest: 70, 78, 79, 81, 81, 81, 82, 86, 90.

Step2: Find the middle value

The data set has 9 values (an odd number of observations). The median is the middle value, which is at the position \(\frac{n + 1}{2}\) where \(n = 9\). So \(\frac{9+ 1}{2}=5\)th position. Looking at the ordered data set: 70 (1st), 78 (2nd), 79 (3rd), 81 (4th), 81 (5th), 81 (6th), 82 (7th), 86 (8th), 90 (9th). The 5th value is 81.

Answer:

81