Question

A simple random sample of 10 people was asked how many first cousins they have. The results are listed below. 10, 19, 20, 13, 13, 2, 10, 8, 25, 10 What is the median number of first cousins for this sample?
7.5
10
11.5
13

Answer 1

Answer:  C)  11.5

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Explanation:

When finding the median, the first task is to sort the values from smallest to largest (aka sort in ascending or increasing order).

The given set

{10, 19, 20, 13, 13, 2, 10, 8, 25, 10}

sorts to

{2, 8, 10, 10, 10, 13, 13, 19, 20, 25}

Because there are n = 10 people in this set, this means the middle value is between slot n/2 = 10/2 = 5 and slot 6.

The values in slots 5 and 6 are 10, 13 in that exact order.

We'll add those values up, and divide by 2 to get the midpoint

(10+13)/2 = 23/2 = 11.5 which is the median.

This trick of "add them up, divide by 2" only applies if n is even.