Answer: B) 89
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Work Shown:
The given list is {95, 89, 99, 85, 82, 81, 99}
Sort this list from smallest to largest.
We then have this: {81, 82, 85, 89, 95, 99, 99}
Next we will erase the first and last items in that sorted list above
Doing so leads to this smaller list: {82, 85, 89, 95, 99}
Repeat the step from before. Erase the first and last items
We now have {85, 89, 95}
One more time lets erase the first and last items getting {89}
This shows that 89 is the very center item
Going back to {81, 82, 85, 89, 95, 99, 99} we see that 89 is at the center with three items below it (81,82,85) and three items above it (95,99,99)
Therefore, the median is 89.
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Another route to take is to count the number of items in {81, 82, 85, 89, 95, 99, 99}. You should count 7 items.
Add 1 and divide by 2 to get (7+1)/2 = 8/2 = 4
The median is in slot 4, which is exactly where 89 is located in the list {81, 82, 85, 89, 95, 99, 99}
Note: this trick only works if you have an odd number of items in a set.