Question 969798
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Go to this site:

http://www.calculator.net/standard-deviation-calculator.html

Type in your values with commas between them like this:
99,34,86,57,73,85,91,93,46,96,88,79,68,85,89

Click on "Calculate":

Read these two values:

Mean (Average):	77.933333333333
Population Standard Deviation, 18.382842241854
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how many scores were within one standard deviation of the mean?
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Add 1 times the standard deviation 18.382842241854 to the mean

77.933333333333 + 1x18.382842241854 = 96.316175575187

Subtract 1 times the standard deviation 18.382842241854 from the mean

77.933333333333 - 1x18.382842241854 = 59.550491091479

List the scores that are between those two numbers:

86,73,85,91,93,96,88,79,68,85,89

Count them:

Answer 11.

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how many scores were within two standard deviations of the mean?
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Add 2 times the standard deviation 18.382842241854 to the mean

77.933333333333 + 2x18.382842241854 = (you do it)

Subtract 2 times the standard deviation 18.382842241854 from the mean

77.933333333333 - 2x18.382842241854 = (you do it)

List the scores between those two numbers:

(you do it)

Count them:

(you do it).

Edwin</pre>