+130071 The mean is 21.75
Std deviation is 7.33
One std deviation from the mean is between 14.42 and 29.08
14 values fall within this...so 14/20 = 70%
Two std deviation lie between 7.09 and 14.42 and from 29.08 and 36.41
5 values fall here = 5/20 = 1/4 = 25%
1 value falls 3 sd deviations from the mean = 1/20 = 5% of data
This data is close to being normally distributed
70% falls within 1 std deviationn......68% is expected
95% falls wihin 2 std deviations......exactly what we expect
And 100% fall within 3 std deviations.....99% is expected
