Quality control is an important issue at ACME Company which manufacturers light bulbs. In order to conduct testing of the life hours of their light bulbs, they randomly sampled nine light bulbs and measured how many hours they lasted (mean = 346.6).
378, 361, 350, 375, 200, 391, 375, 368, 321

-What is the variance?
A)342.43
B)3424.3
C)58.5
D)191
E)10609

Question

Quality control is an important issue at ACME Company which manufacturers light bulbs. In order to conduct testing of the life hours of their light bulbs, they randomly sampled nine light bulbs and measured how many hours they lasted (mean = 346.6).
378, 361, 350, 375, 200, 391, 375, 368, 321

-What is the variance?
A)342.43
B)3424.3
C)58.5
D)191
E)10609

Quizplus · Accepted Answer

The variance is calculated by finding the average of the squared differences from the mean. First, find the mean (346.6), then calculate each bulb's squared difference from the mean, sum these squared differences, and divide by the number of observations (9). This results in a variance of 3424.3.

Quality Control Is an Important Issue at ACME Company Which