40, 45, 50, 55, 65, 75, 75, 100, 100, 100.
The list above shows the scores of 10 schoolchildren on a certain test. If the standard deviation of the 10 scores is 22.2, rounded to the nearest tenth, how many of the scores are more than 1 standard deviation below the mean of the 10 scores?
Select:
A) 1	B) 2	C) 3	D) 4	E) 5
The average of {40, 45, 50, 55, 65, 75, 75, 100, 100, 100} is 70.5   1 standard deviation below the mean is 70.5 - 22.2 = 48.3. Hence there are two scores (40 and 45) more than 1 standard deviation below the mean.   Answer 2.
<result>B</result>
40, 45, 50, 55, 65, 75, 75, 100, 100, 100.
The list above shows the scores of 10 schoolchildren on a certain test. If the standard deviation of the 10 scores is 22.2, rounded to the nearest tenth, how many of the scores are more than 1 standard deviation below the mean of the 10 scores?