SOLUTION: Compute the standard deviation and variance of two student's quiz grades. Which student has performed more consistently? Student A quiz grades: 8,7,5,6,19 Student B: 2,3,13,5,6

Algebra ->  Probability-and-statistics -> SOLUTION: Compute the standard deviation and variance of two student's quiz grades. Which student has performed more consistently? Student A quiz grades: 8,7,5,6,19 Student B: 2,3,13,5,6      Log On


   

Question 1052581: Compute the standard deviation and variance of two student's quiz grades. Which student has performed more consistently?
Student A quiz grades: 8,7,5,6,19
Student B: 2,3,13,5,6
Answer by Boreal(15235) About Me  (Show Source):
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The first has a sd of 5.70 (using sample) and variance of 32.49 and the second 4.32, with variance of 18.66. The second has performed more consistently than the first with less variance.
The mean of the first is 9
the squared differences from that 9 are (8-9)^2 or 1, and 4, 16,9, and 100. That is divided by 4 to get 32.5, and the square root of that is 5.70. The second is done the same way.