Six students from a psychology class reported the number of hours of television they watch per week.Here are their data: 18, 12, 15, 14, 13, 16.The variance of the number of hours of television watched per week for this sample of six students is:
A) 1.97.
B) 3.89.
C) 15.13.
D) 23.33.

Question

Quizplus · Accepted Answer

1. Calculate the mean: 
(18 + 12 + 15 + 14 + 13 + 16) / 6 = 14.67 
2. Subtract the mean from each observation and square the result: 
(18 - 14.67)^2 = 4.4556 
(12 - 14.67)^2 = 7.1689 
(15 - 14.67)^2 = 0.1089 
(14 - 14.67)^2 = 0.4489 
(13 - 14.67)^2 = 2.7689 
(16 - 14.67)^2 = 1.7889 
3. Sum the squared deviations: 
4.4556 + 7.1689 + 0.1089 + 0.4489 + 2.7689 + 1.7889 = 16.74 
4. Divide by the sample size minus 1: 
16.74 / (6 - 1) = 3.348 
Therefore, the variance is 3.348, which is closest to 3.89 (answer choice B).

Six Students from a Psychology Class Reported the Number of Hours