Answers:
median = 25
mean = 29
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Explanation
We need to sort the data from smallest to largest so we can locate the median.
original data = {7, 47, 43, 47, 25, 16, 18}
sorted data = {7, 16, 18, 25, 43, 47, 47}
There are n = 7 values in this set, then compute n/2 = 7/2 = 3.5 which rounds to 4. The median is found in slot 4. There are 3 values below the median and 3 values above it (making 3+1+3 = 7 values total).
The value in slot 4 is 25 which is the median.
Another way to find the median is to repeatedly cross off the first and last values of the set. It will shrink the set gradually until the middle-most value is very obvious.
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To find the mean, we don't need to sort the values. But it doesn't affect the answer if we do or not.
To get the mean, we add up the values. Then we divide by the sample size n = 7.
Add: 7+16+18+25+43+47+47 = 203
Divide over sample size: 203/n = 203/7 = 29 is the mean