What does an standard deviation of 4.23 means if the mean score is 18.42?

Question

What does an standard deviation of 4.23 means if the mean score is 18.42?

Answer 1

4.23 standard deviation with a mean score of 18.42 means the following.



18.42 plus or minus 4.23 (68% of the data falls inside this range) One deviation

18.42 plus or minus 8.46 (95% of the data falls inside this range) Two deviations

18.42 plus or minus 12.69 (99.7% of the data falls inside this range) Three deviations



So three deviations (using your information) results in a range of 5.73 to 31.11



Anything outside this range is considered an outlier.