In a hearing test, randomly selected subjects estimate the loudness (in decibels) of a sound, and the results are (mean = 70): 68, 67, 70, 71, 68, 75, 68, 62, 80, 73, 68. What is the variance?
A) 18
B) 4.73
C) 22.40
D) 324
E) 6.76

Question

Quizplus · Accepted Answer

62, 67, 68, 68, 68, 68, 70, 71, 73, 75, 80
(62 − 70)= -8 squared = 64
(67 − 70)= -3 squared = 9
(68 − 70)= -2 squared = 4
(68 − 70)= -2 squared = 4
(68 − 70)= -2 squared = 4
(68 − 70)= -2 squared = 4
(70 − 70)= 0 squared = 0
(71 − 70)= 1 squared = 1
(73 − 70)= 2 squared = 4
(75 − 70)= 5 squared = 25
(80 − 70)= 10 squared = 100
(64 + 9 + 4 + 4 + 4 + 4 + 0 + 1 + 4 + 25 + 100) = 224 / 10 = 22.40

In a Hearing Test, Randomly Selected Subjects Estimate the Loudness