A nationwide survey of 100 boys and 50 girls in the first grade found that the daily average number of boys who are absent from school is 15, with a standard deviation of 7. For girls, the average number of absentees is 10, with a standard deviation of 6.
The standard deviation of the difference is BLANK.

Question

A nationwide survey of 100 boys and 50 girls in the first grade found that the daily average number of boys who are absent from school is 15, with a standard deviation of 7. For girls, the average number of absentees is 10, with a standard deviation of 6.
The standard deviation of the difference is BLANK.

odotellessa · Answer

huh, 15 of 100 boys, in what country is this? 

Mate! Draw pictures! Pictures are awesome figuring out stuff like this :D and it's fun.