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junior college 1 | H2 Maths
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Hi why is the variance 3.06 and not 2.52? Please help me thankuu in advance!! :)
Date Posted: 4 years ago
Views: 349
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E(X²) = 0² × 0.54 + 1² × 0.16 + 2² × 0.06 + 3² × 0.04 + 4² × 0.20 = 3.96
E(X) = 0 × 0.54 + 1 × 0.16 + 2 × 0.06 + 3 × 0.04 + 4 × 0.20 = 1.2
Var(X) = E(X²) - (E(X))² = 3.96 - (1.2)² = 3.96 - 1.44 = 2.52
Answer key seems to be erroneous
E(X) = 0 × 0.54 + 1 × 0.16 + 2 × 0.06 + 3 × 0.04 + 4 × 0.20 = 1.2
Var(X) = E(X²) - (E(X))² = 3.96 - (1.2)² = 3.96 - 1.44 = 2.52
Answer key seems to be erroneous
Ya I think ans key may be wrong. Thank you for helping!!
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