Question

Given the following list of data, find the median. 21,28,30,31,17,16,12 Give your answer as a number only. For example, if you found the median was 17, you would enter 17.

Answer 1

21

Explanation:

arrange the values in ascending or descending order and find the middle number, if there are 2 numbers in the middle, add them and divide by 2

12 16 17 21 28 30 31

21 is the median because this is the number in the middle

Answer 2

Answer: 21

Explanation

Given data set = {21, 28, 30, 31, 17, 16, 12}

Sorted data set = {12, 16, 17, 21, 28, 30, 31}

There are n = 7 items in this set. This is the sample size. Because the sample size is an odd number, we can find the middle index by computing n/2 = 7/2 = 3.5 which rounds up to 4.

The 4th slot is where the middle is located. We have 3 values below the median and 3 values above (giving 3+1+3 = 7 values total).

The number 21 is in the 4th slot, so it is the median.

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Another way to find the median is to cross off the first and last values in the sorted set.

We go from {12, 16, 17, 21, 28, 30, 31} to {16, 17, 21, 28, 30}

Repeat that process to get to {17, 21, 28} and it should be very clear at this point that 21 is at the very middle. I've marked them in bold to help show this better.