Answer :
You don't even have to look up the definition of 'standard deviation'. You only
have to remember that 'smaller standard deviation' means 'less spread-out'.
First, let's find the mean (average). It's not supposed to change:
1/7th of (65 + 71 + 77 + 80 + 82 + 90 + 96) = 561/7 = 80 and 1/7 .
Now, just pick 7 scores that total 561 and are all bunched up.
The easiest way would be 80, 80, 80, 80, 80, 80, 81 .
But that's so easy that it feels like cheating.
Let's say 77, 78, 79, 80, 81, 82, and 84 .
have to remember that 'smaller standard deviation' means 'less spread-out'.
First, let's find the mean (average). It's not supposed to change:
1/7th of (65 + 71 + 77 + 80 + 82 + 90 + 96) = 561/7 = 80 and 1/7 .
Now, just pick 7 scores that total 561 and are all bunched up.
The easiest way would be 80, 80, 80, 80, 80, 80, 81 .
But that's so easy that it feels like cheating.
Let's say 77, 78, 79, 80, 81, 82, and 84 .
