A consumer organization inspecting new cars found that many had appearance defects. While none had more than 3 defects, 7% had three, 11% had two, and 21% had one defect. Find the expected number of appearance defects in a new car, and the standard deviation.

Question

Mathematics

Howard Cannon

29 September, 22:00

A consumer organization inspecting new cars found that many had appearance defects. While none had more than 3 defects, 7% had three, 11% had two, and 21% had one defect. Find the expected number of appearance defects in a new car, and the standard deviation.

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Answers (1)

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Maren Leblanc · Answer 1

E (X) = 0.64

Sd (X) = 0.933

Step-by-step explanation:

3 (0.07) + 2 (0.11) + 1 (0.21)

E (X²) = 3² (0.07) + 2² (0.11) + 1² (0.21)

= 1.28

Var (X) = 1.28 - 0.64² = 0.8704

Sd = 0.933