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

Question

Mathematics

Giada

4 August, 00:59

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

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Selene · Answer 1

Te difference of 2 standard deviation of a population n1 & n2 is given by the formula:

sigma (difference) = √ (sigma1/n1 + sigma2/n2), Plug:

sigma (d) = √ (49/100 + 36/50)

Sigma (d=difference) = 1.1