Help on Statistics Problems Solved

In this article let me help you on statistics problems solved. Since we had studied enough on statistics let me help you with the sample problems.

Following is the sample problem on statistics:

Problem 1

For boys, the average number of absences in the first grade is 15 with a standard deviation of 7; for girls, the average number of absences is 10 with a standard deviation of 6.

sample?

(A) 0.025
(B) 0.035
(C) 0.045
(D) 0.055
(E) None of the above
Solution

The correct answer is B. The solution involves four steps. This could also help us on statistics answers online
* Find the mean difference (male absences minus female absences) in the population.
μd = μ1 - μ2 = 15 - 10 = 5

* Find the standard deviation of the difference.
σd = sqrt( σ12 / n1 + σ22 / n2 )
σd = sqrt(72/100 + 62/50) = sqrt(49/100 + 36/50) = sqrt(0.49 + .72) = sqrt(1.21) = 1.1

* Find the z-score that produced when boys have three more days of absences than girls. When boys have three more days of absences, the number of male absences minus female absences is three. And the associated z-score is
z = (x - μ)/σ = (3 - 5)/1.1 = -2/1.1 = -1.818


Therefore, the probability that the difference between samples will be no more than 3 days is 0.035.