A teacher grading statistics homework finds that none of the students has made more than three errors.14% have made three errors,25% have made two errors,and 39% have made one error.Find the standard deviation of the number of errors in students' statistics homework.
A)0.97
B)0.93
C)0.89
D)1.07
E)0.82

Question

Quizplus · Accepted Answer

The standard deviation is the square root of the variance. The variance is the average of the squared deviations from the mean. The mean is the average number of errors. The variance is calculated as follows:Variance = (0.14 * (3 - 1.4)^2) + (0.25 * (2 - 1.4)^2) + (0.39 * (1 - 1.4)^2) + (0.22 * (0 - 1.4)^2) = 0.94The standard deviation is the square root of the variance, which is 0.97.

A Teacher Grading Statistics Homework Finds That None of the Students